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Notation on an engineering drawing or schematic that instructs how a part is made or a system assembled.
All 506symbols recorded in this context, A–Z.
A halving series of sheet sizes, from A0 at one square metre downward.
A number held in beads.
Cast lettering and a load class on a manhole or inspection cover.
A rounded vessel storing energy under pressure.
A restriction crossed by an adjustment arrow.
A shaft with blades, mixing a vessel's contents.
A circle with an open triangle pointing outward.
A vessel removing moisture from compressed air.
A rectangle housing fans, filters and coils.
A circle with an open triangle pointing inward.
A closed vessel storing compressed air.
Filter, regulator and lubricator grouped in one outline.
A tube bank with a fan drawn beneath it.
A circle or a double circle on a leader, extending a callout.
A circle containing a capital A, measuring current.
An instrument bubble tagged for composition measurement.
A flat-backed D shape, outputting true only when every input is true.
An angle sign in a frame, controlling orientation to a datum.
A stem branching into two upward diagonals.
A fixed point all measurements refer to.
A marked point locating an object.
Short strokes showing a cut edge.
A bounded area of excavation.
Which side of the joint gets the weld.
A head marked at a single point on the rail.
Two angles fixing a direction from where you stand.
A valve bowtie with an open circle at its centre.
A dimension in a rectangle, exact by definition.
A long rounded rectangle with a drain mark.
Alternating long and short parallel lines, marking a cell or battery.
A Greek letter with a constellation's genitive name.
Two parallel lines with end pulleys carrying solids.
Half a V.
A pump circle with two solid triangles pointing opposite ways.
Hinged leaves folding back against each other.
A line beyond the trim showing overprint.
A rotating machine outline moving gas at low pressure.
A name, a definition sign and alternatives.
The pressure it was built for.
A rectangle marked as the heat source of a system.
Numbers or radial lines on a head giving tensile strength.
A marked point recording where the ground was drilled.
A fixed stone or marker defining a legal boundary.
A jagged or looped line marking omitted length.
A tank fitting admitting and venting air.
Diagonal hatching marking brickwork cut in section.
A vertical casing with buckets on a loop.
A plain triangle passing its input through unchanged.
A valve bowtie with a diagonal disc line.
A T-shaped mark on a plan showing who maintains a boundary.
Letters after a year saying which era it counts from.
Two parallel lines across a break in a wire, marking a capacitor.
A wall opening with glazing lines and a swing arc.
A circle with crossed lines marking a light point.
Two great circles drawn across a star chart.
A long-dash-dot line marking an axis of symmetry or a circle's centre.
A tapering outline compressing gas continuously.
A circle with a triangular wedge, marking a pump and its flow direction.
A bowl outline separating by spinning.
One contact that can meet either of two others.
A rake of three short diagonal strokes under a stem.
A ball or flap against a seat, permitting flow one way only.
A switch drawn with a marking showing automatic operation.
A plain circle inside a tolerance frame.
Four digits in one figure.
A board and a bang, together.
A valve centre square with all four ports blocked.
A line inside a partial enclosure, marking a screened conductor.
A small black block on a section's spine, stepping down the book when gathered.
A strip of ink patches along a sheet edge, used to measure printing quality.
A lettered and numbered grid locating structure.
A curve hollowed inward.
Two circles sharing a centre in a tolerance frame.
Scattered dots and triangles marking concrete in section.
Two numbers giving crushing strength at twenty-eight days.
Three letters standing for one of eighty-eight constellations.
A rectangle marking the origin of an installation.
A relay coil driving heavy-current contacts.
A number identifying one deposit, cut or structure.
A circle with a single horizontal line across it.
A valve body with an actuator drawn above it.
A curve bulging outward.
A diamond with arrows pointing outward, shedding heat.
A tapered outline with a fan and water lines.
A struck-through marginal instruction.
A valve holding back a load against gravity.
A flat-bottomed bracket shape, calling for a flat-bottomed enlarged hole.
A shallow V shape, calling for a conical widening at a hole's mouth.
Rods laid out in place columns.
A small oval in a chart.
Several strokes joined at the foot.
A small loop on the edge of a row.
A fan of strokes from one point.
A filled dot in a chart.
Short right-angled lines at each corner, showing where a sheet is to be trimmed.
Two lines crossing without a dot, not connected.
A splayed end meaning many.
A crystal drawn with two capacitors to ground.
A small rectangle between two plates, marking a quartz frequency reference.
Names and axis descriptions classifying a crystal's symmetry.
A circle with an arrow, delivering a set current.
A cylinder with a small rectangle marking end-of-stroke braking.
A cylinder above a cone, separating solids from gas.
A rectangle with a piston and rod showing how it acts.
A circle between two slanting lines in a tolerance frame.
A boxed letter on a filled or open triangle, establishing a reference.
A divided circle naming a point, line or area of contact.
A celestial coordinate measured in degrees north or south.
A delete loop with closing arcs.
A triangle marking three windings joined end to end.
A downward arrow saying how deep a hole goes.
A circle around an area, referring to a larger drawing.
A notched bar holding a valve in its selected position.
A circle with a diagonal stroke, marking a dimension as a diameter.
A valve body with a curved diaphragm line.
A triangle pointing at a bar, marking a diode.
Adjacent boxes whose arrows show each switched position.
A tall vessel with internal lines marking trays.
A gap in a wall with a quarter-circle arc showing the swing.
A wall gap with two leaves and two opposing arcs.
A rectangle with a piston rod out both ends.
Continuous, dashed and chain lines each meaning something different.
Size, material and tip type stamped on the shank.
Cuts in an animal's ear encoding an owner or a number.
Irregular hatching marking undisturbed ground.
A number on a logarithmic scale, subscripted by method.
Square brackets marking an optional part.
Braces marking a repeatable part.
Codes naming an eclipse's type, date and magnitude.
Two uprights side by side.
A circle with an arrow pointing at the face to be drawn.
A light symbol marked for operation on power failure.
A dash-dot outline grouping components in one housing.
Vertical strokes marking uneven spacing.
A long rectangle with step lines and a direction arrow.
A circle with blades removing air from a room.
A heavy line with ticks or arrows showing which side moved.
Lines that stand for an integral.
A small flag saying the weld is made on site.
A flag meaning not in the shop.
A plain circle marking an instrument out in the plant.
A right triangle marking a weld in the corner of a joint.
Numbers printed along the perforations.
A stack of plates dewatering a slurry.
A diamond with a dashed line across its short axis.
A filter diamond with a check valve alongside it.
A small square marking a manual alarm point.
A duct fitting closing where a duct crosses a barrier.
A chamber outline with burner marks and a stack.
A truncated cone shown in two views, stating which projection convention a drawing uses.
A circle with one solid triangle pointing inward.
A circle with one solid triangle pointing outward.
A line narrowing at a point to restrict flow.
A wall opening with glazing lines and no arc.
A fitting with a hatched element stopping flame travel.
A parallelogram, specifying how flat a surface must be.
A bowed line marking a flexible connection.
A valve centre with actuator ports joined to tank.
A tank outline with an internal line for a moving roof.
A small square or circle marking a floor drain.
A block splitting one flow into two fixed proportions.
An instrument bubble tagged as a flow controller.
An instrument bubble tagged for flow transmission.
A small lettered circle joining flows.
A diamond with labelled exits.
An arrow joining one step to the next.
A slanted parallelogram.
A rectangle with doubled side bars.
A plain rectangle for an operation.
Shapes standing for kinds of step.
A rounded shape starting or ending a flow.
Solid, dashed and dot-dashed lines for working, pilot and drain.
A straight bar meaning dress it flat.
An arrowed line showing where rock has been bent.
A dashed line outside the trim, showing where a sheet is folded.
Paint bands and dots marking trees for felling or retention.
A mark where two routes begin to conflict.
A circled F applying a tolerance to an unrestrained part.
Letters and numbers stating a fuse's current, speed and voltage.
A rectangle with a line through it, marking a fuse.
An accumulator oval divided by a bladder line.
Two triangles meeting at their points, the generic valve on a flow diagram.
Colours standing for the age of the rock beneath.
Letters printed on a map naming the rock's age.
A rectangular box divided into cells, stating a geometric characteristic and its tolerance.
A valve bowtie with a filled circle at its centre.
An arrow or an underlined dimension on a ream wrapper, showing paper grain.
An arrow saying which way the cloth runs.
A contour of gravitational variation.
Shapes naming how the joint edges are prepared.
A pump circle with a lever handle attached.
Helmet colours identifying roles on a construction site.
A diagram of stratigraphic relationships in an excavation.
A boxed context number in a diagram.
A line stating which context is earlier.
A circle or rectangle crossed by a zigzag, marking heat transfer between streams.
A diamond with arrows pointing inward, adding heat.
A line of short even dashes, showing an edge concealed behind material.
A long rectangle with domed ends, lying on its side.
A tall rounded vessel storing heated water.
A serpentine line with a drain connection.
A tapered joint between two duct sizes.
A circle with angled blades.
A hatched band across a duct.
A ribbed double line.
A serpentine line across a duct.
A duct section with rising droplets.
A circle carrying a letter code.
A circle with a solid triangle pointing out of it.
A short stub with a cross, for connecting a gauge.
A circle with a plus and minus or a bar, holding a set voltage.
A plain rectangle with a symbol inside naming the function.
A row of humps or a filled rectangle in a wire, marking an inductor.
A coloured band or tag showing the period in which equipment was last inspected.
A circle with letters and a number tagging a process instrument.
Patterned lines distinguishing pneumatic, electric and software signals.
Letters in an instrument bubble naming its function.
A soft looping line marking thermal insulation.
A small circle on a lead marking active-low behaviour.
A ringed note marking an upside-down type.
Two digits for dust and water.
Year, month and day in fixed order, largest unit first.
A year, a W and a week number.
Half a U.
A field-effect transistor whose gate touches the channel.
A ten-degree shaking scale written as shindo.
A continuous count of days used in astronomy.
A filled dot where two wires are connected.
A crossed band leaning right.
A crossed band spanning several squares.
A vertical stroke with side strokes.
A blank or plain square in a chart.
A stroke leaning right in a chart square.
A small looped mark in a chart square.
A dot or dash in a chart square.
A stroke leaning left in a chart square.
A small open circle in a chart square.
A crossed or straight pattern note specifying a gripping surface.
A circle with a cross inside it, marking a lamp or indicator.
Thin lines with arrows tying a note or a size to a feature.
A diode symbol with two arrows pointing away, marking a light-emitting diode.
A triangle or circle marking a stated height.
An instrument bubble tagged as a level controller.
An instrument bubble tagged for level transmission.
A short lever drawn against a valve block.
A rectangle with crossed diagonals marking a lift car.
A resistor in a circle with two arrows pointing at it.
A small circle with a short stroke on a wall.
A design burned or frozen into hide, read by a fixed grammar.
A numbered tag identifying an individual animal.
A table that is a limit.
Shapes standing for boolean functions.
A rectangle opening into a trumpet shape.
A bracket pushing matter downward.
A vessel adding oil mist to an air stream.
Shaded discs showing how much of the moon is lit.
Corrections read left to right across a line.
A circled M allowing extra tolerance as a feature shrinks.
A curve meaning it must reach the back.
An M and a number naming a deep-sky object.
Weather compressed into one line.
A circle on a stem, converting sound into signal.
A date recording when work stopped.
A line where a seam meets the surface.
A hatched area of extracted ground.
Painted or fixed points recording position underground.
A number from one to ten ranking scratch resistance.
A three-terminal transistor with a gate bar separated by a gap.
A circle containing the letter M, marking an electric motor.
A bracket pushing matter to the left.
A bracket pushing matter to the right.
An AND gate with an inverting circle on its output.
Stencilled lettering on an aircraft surface marking unsupported skin.
Three scales and a straight edge.
Letters on a reference line calling for a named inspection method.
An OR gate with an inverting circle on its output.
A triangle with a small circle at its point, inverting the input.
A valve centre square with all four ports joined.
A triangle pointing right with two marked inputs.
An LED facing a phototransistor inside one box.
A curved-back shield shape, outputting true when any input is true.
Two short lines across a pipe, measuring flow by pressure drop.
A circle with two triangles and a limited-rotation arrow.
A tall vessel with a hatched or shaded internal zone.
One mark in the text, one in the margin.
Two slanting parallel lines in a tolerance frame.
A foot pedal shape marking foot operation.
Tensors drawn as shapes with legs.
An upright T on a base line, specifying squareness to a datum.
Tokens moving between places.
A diode with two arrows pointing towards it.
A dashed line and rectangle marking pressure actuation.
A check valve with a pilot line able to force it open.
An in-line fitting with a mesh element catching debris.
A rectangle with closely spaced parallel lines.
A valve bowtie with a rectangle at its centre.
A rectangle on the line.
A cross marking a port closed off.
A pair of check valves with a relief.
A capped branch off a drain.
A chambered box on a drain run.
A circle marking a pipe running vertically.
A U-shaped bend in a drain line.
An adjustable valve holding a set downstream air pressure.
A sliding leaf disappearing into a wall cavity.
A box drawn beside a set of points.
A capacitor with one curved plate and a plus mark.
A plus, a minus, a bar or a chamfer showing which way round.
A crossed circle limiting where a feature may sit.
A pump outline moving a fixed volume per stroke.
A resistor with an arrow touching it, marking a variable division of voltage.
A vessel drawn half in section and half in elevation.
A circle on a stem with a pointer or letters, marking a pressure indicator.
A valve square held open, sensing downstream pressure.
An angled valve body with a spring above it.
An instrument bubble tagged for pressure transmission.
An adjustable restriction with a compensating element.
A closed rectangle holding fluid above atmospheric pressure.
An exchanger condensing vapour to liquid.
Line weight distinguishing main process flow from services.
A half-circle, open or closed, controlling a whole shape.
A circle inside a diamond, marking logic functions.
A circled P extending a tolerance zone beyond the part.
A height measuring how far a summit rises above its saddle.
A signed and dated box on a proof, transferring responsibility for the content.
A circle enclosing a three-bar earth glyph — IEC 60417-5019, marking the protective earth (ground) terminal on Class I equipment.
A small tee shape marking hand-button operation.
A contact operated by a stem with a bar on top.
A three-port valve venting a cylinder locally.
Opposed brackets marking a connector that can be parted.
A long narrow rectangle against a wall.
A date with an error, a laboratory code and a calibration marker.
A capital R before a dimension, marking it as a radius.
A short stub diverging from a running line.
A bracket lifting matter upward.
A sloping surface with an arrow marking the rise.
A vessel outline marked as a place of reaction.
An exchanger returning vapour to a column base.
A cylinder and piston outline compressing gas in strokes.
Two parallel lines carrying air, sized on the drawing.
A fine circle crossed by a full-length cross, used to align printing plates.
A coil beside a switch, showing a circuit that a second circuit operates.
A single box with an arrow and a spring, limiting pressure.
A breaker marked with a current-comparison box.
A zigzag or a plain rectangle in a circuit, marking a resistor.
A square with inward lines drawing air back.
A scalloped outline around what has changed since the last issue.
A circle with radiating leaves in an opening.
A celestial coordinate measured in hours rather than degrees.
A circle drawn round a written instruction.
A graduated board or post showing water level.
Repeating patterns standing for rock type in a section.
A small circle on a stem, tripped by a passing part.
A stroke joining two paragraphs.
One or two slanting arrows controlling wobble about an axis.
A line with a bowed membrane, bursting to relieve pressure.
A coloured tag at a scaffold access point recording its inspection status.
A diode whose bar ends turn like a letter S.
A trough with a helical line moving solids.
Recess shapes naming how a fastener is turned.
A circle crossed by a bar.
A heavy line with end arrows marking where a section is taken.
A vertical slice, drawn to rule.
Hachures, levels and a datum line recording a vertical face.
Diagonal lines showing solid material a cut has passed through.
A shaded wave against two-way time.
A normally closed valve opening at a set inlet pressure.
A struck-through capital with a marginal note.
A ringed instruction cancelling a style.
A double underline beneath matter.
A bar with end strokes.
A solid outline round a piece.
A circle inside a square, marking a shared control system.
A cylinder with tube lines running through it.
A dashed rectangle around part of a circuit.
A square tray with a drain and diagonal lines.
A ball in a tee, passing the higher of two pressures.
A clock keyed to the stars rather than to the sun.
An in-line fitting allowing flow to be seen.
A solid downward triangle marking a common reference.
A tapered outline on an exhaust port.
A rectangle with a piston rod out one end and one port.
A heavy line carrying connections.
A square drawn on a conductor line.
A hinged blade breaking a line.
A circle carrying a letter G.
Two overlapping circles on a line.
A transformer tapped off a conductor.
Numbers spaced by logarithm.
A wall gap with a leaf drawn parallel to the wall.
A tag that must be legible or the sling is scrap.
A circle marked S on a ceiling position.
A semicircle on a line, marking a power point.
A letter marking a mineral topsoil.
A letter marking a subsoil of accumulation.
A letter marking little-altered parent material.
Capital letters naming layers down a soil profile.
A letter marking an organic layer.
A triangle plotting three particle fractions.
A circle in plan marking a vertical drainage stack.
A coil marked as producing mechanical movement.
One bead above, four below.
A number giving the distance across the flats.
A capital S before the diameter sign.
Wedge-shaped treads radiating around a centre.
A circle on the line.
A zigzag spring returning a valve to its rest position.
An accumulator oval with a spring drawn inside.
A small circle marking a suppression outlet.
Two parallel uprights.
A small square before a dimension, marking a square feature.
Parallel lines with an arrow marking direction of travel.
Dots of graded size standing for brightness.
Three lines meeting at a common point.
A marked callout permitting statistical rather than worst-case control.
A fitting discharging condensate but holding steam.
Letters and numbers naming composition and strength.
Close diagonal hatching marking structural steel.
A number that runs backwards, smaller meaning brighter.
A rectangle with flat ends, holding liquid at atmosphere.
A single straight line inside a tolerance frame.
A long line with a short tick and a number, giving a bed's attitude.
A square with radiating lines delivering air.
A check-mark-like tick with a long arm, carrying surface texture requirements.
A mark saying which way the machining marks must run.
A tick with added bars and numbers specifying roughness.
Two stacked arcs.
A break in a wire bridged by a hinged line, marking a switch.
Three horizontal lines in a tolerance frame.
The same grammar, in the future tense.
A valve centre with pump joined to tank and ports blocked.
Two shallow triangles distinguishing a cone from a wedge.
Nested rectangles showing a multi-stage ram.
An instrument bubble tagged as a temperature controller.
An instrument bubble tagged for temperature transmission.
A small hollow circle where a wire can be connected.
A small marked node intended for measurement.
A resistor crossed by a line marked with a temperature sign.
A truncated cone in two views, mirrored from the first-angle symbol, stating the American convention.
A letter code and numbers naming a screw thread completely.
Three lines with a numeral and phase notation.
Three squares side by side with four connections.
A valve body with three connections instead of two.
A diode with a gate lead, latching once triggered.
Times and heights of high and low water at a named port.
A stamp giving strength class, moisture and certification.
Grain lines marking sawn timber cut across.
A Z or a signed offset fixing a time to a zone.
Colour written in lines.
A bracketed section of a drawn track line.
Two coils facing each other across parallel lines, marking a transformer.
An arrow on one lead showing the device's polarity.
Two thyristors drawn back to back with one gate.
Two squares side by side with two connections.
A switch symbol marked for control from two points.
A U on the line.
A narrow rectangle on a lifeline.
A stick figure standing for a role.
A line ending in a hollow diamond.
A plain line joining two classes.
A rectangle divided into three bands.
A line ending in a filled diamond.
A dashed line with an open arrowhead.
A line ending in a hollow triangle.
A dashed vertical line below a participant.
Figures at the end of an association line.
An oval containing a goal.
A sign prefixing a member name.
A wavy line marking missing time in a rock sequence.
A serpentine line covering a floor area.
Coloured printed tape laid above a buried cable or pipe as a last warning.
A valve returning pump flow to tank at low pressure.
Sprayed letters and figures giving a buried service's size, material and depth.
Coloured paint before you dig.
Spray-painted colours on a road surface, each standing for a buried service.
A V on the line.
A converging nozzle producing suction from air flow.
A cup shape gripping a workpiece by suction.
A capacitor with an arrow drawn across its plates.
A motor circle crossed by a diagonal arrow.
A pump circle crossed by a diagonal arrow.
Letters assigned in an order almost nobody can guess.
A resistor marked with a voltage-dependence stroke.
An open-topped rectangle holding the system fluid.
A tall rectangle with domed ends, drawn upright.
A number from zero to eight rating an eruption's size.
A circle containing a capital V, measuring potential difference.
A duct fitting adjusting the air passing through.
A circle for calibrating a receiver.
A rounded bowl outline against a wall.
A rounded pan outline with a cistern behind it.
An accumulator with a weight drawn above the piston.
Which side of the reference line a weld symbol sits on.
A line and letter saying what shape the finished weld must be.
A code in the tail of a welding symbol naming the process.
A circle meaning go right round.
A circle at the reference line's elbow, calling for a continuous weld.
The line every weld symbol hangs on.
An arrow and horizontal reference line carrying weld type, size and process.
A fork carrying the process.
Two curves swapping order to flag a zone.
A vertical strip carrying one measurement.
A small semicircular hop where wires cross without joining.
A number that gets larger as the wire gets thinner.
An OR gate with a second curved line across its back.
A diode whose bar has bent ends like a letter Z.