Set in small capitals mark

A double underline beneath matter.

Also known as: Set in small capitals proof mark, Double underline proofreading

Engineering & technicalEveryday & digitalStandard profile

Meanings

The proof correction mark instructing that matter be set in small capitals, drawn as two underlines.

Officially standardisedVerified fact
Instructs that matter be set in small capitals.
Contexts: Technical drawing
Officially standardisedVerified fact
Sits between the italic mark's one line and the capitals mark's three, the whole scheme stopping at three because four lines cannot be told from three at a glance.
Contexts: Technical drawing

Visual description

Two straight lines drawn one below the other beneath the matter.

Symmetry: none
Orientation: upright

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references.

Sources

BS 5261 — Copy preparation and proof correction
British Standards Institution · retrieved 2026-08-21
The British Standard defining proof-correction marks and their marginal counterparts. Paywalled, so records describe the marks as documented in secondary summaries of the standard rather than quoting its text. Authoritative for British practice; American convention differs in several marks.
The Chicago Manual of Style
University of Chicago Press · retrieved 2026-08-21
The principal American style authority, including its table of proofreaders' marks. Authoritative for American publishing convention; British practice under BS 5261 differs in several marks and in the use of colour.

Last reviewed 2026-08-24

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Meanings

The proof correction mark instructing that matter be set in small capitals, drawn as two underlines.

Officially standardisedVerified fact

Instructs that matter be set in small capitals.

Contexts: Technical drawing

Officially standardisedVerified fact

Sits between the italic mark's one line and the capitals mark's three, the whole scheme stopping at three because four lines cannot be told from three at a glance.

Contexts: Technical drawing

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references.

Sources

BS 5261 — Copy preparation and proof correction
British Standards Institution · retrieved 2026-08-21
The British Standard defining proof-correction marks and their marginal counterparts. Paywalled, so records describe the marks as documented in secondary summaries of the standard rather than quoting its text. Authoritative for British practice; American convention differs in several marks.
The Chicago Manual of Style
University of Chicago Press · retrieved 2026-08-21
The principal American style authority, including its table of proofreaders' marks. Authoritative for American publishing convention; British practice under BS 5261 differs in several marks and in the use of colour.

Last reviewed 2026-08-24