Two horizontal strokes meaning equality in mathematics and a licence restriction on a creative work.
Between two quantities, two level strokes assert that they are equal. Enclosed in a circle on a licensed work, the same two strokes are the no-derivatives condition: the work may be shared, but modified versions may not be distributed. Adapting it privately is not restricted — the condition is about sharing the result.
The mathematical equals sign asserts equality; enclosed in a circle on a licensed work it means no derivative versions may be distributed.
Drawn from the visual attributes recorded for each symbol. Only traits the two records disagree about are listed.
| Trait | No-derivatives mark (ND) | Equals sign |
|---|---|---|
| Built from | circles, lines and dots | lines and dots |
| Enclosing border | Sits inside a border | No enclosing border |
| Orientation | upright | orientation independent |
| No-derivatives mark (ND) | Equals sign | |
|---|---|---|
| Where | In an expression | In a circle, on a licensed work |
| What it means | The two sides are equal | Do not distribute modified versions |
| Enclosed in a circle | No | Yes |
| Restricts private changes | — | No, only sharing them |
| Relationship (from Symbolwise's records) | Commonly confused with Equals sign — The mathematical equals sign asserts equality; enclosed in a circle on a licensed work it means no derivative versions may be distributed. | Commonly confused with No-derivatives mark (ND) — The mathematical equals sign asserts equality; the same two strokes in a circle on a licensed work forbid distributing modified versions. |
Creative Commons Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0)
Creative Commons · retrieved 2026-08-01
The issuing body's own published deed. Authoritative for what the licence permits and requires, and for the mark that denotes it. It is not legal advice, and it says nothing about whether a given work is validly licensed — only what the licence means if it is.
Robert Recorde (1510–1558) — Biography
MacTutor History of Mathematics, University of St Andrews · retrieved 2026-07-26
Two short parallel lines. Between atoms in a structural formula they are a double bond — two shared electron pairs. Between quantities they assert equality. There is no visual difference at all, and none is needed, because the two never appear in the same expression.
Count the horizontal strokes. One assigns a value. Two compare after converting types, which is where surprising results come from. Three compare without converting, so a string and a number are never equal. Miscounting is among the most common mistakes made by people new to the language, and nothing in the shape warns you.
The contactless indicator is four nested arcs and marks a payment card or terminal. The N-Mark is a wave-like capital N, is a trademark of the NFC Forum, and marks where to tap a device for near-field communication generally. The underlying radio technology overlaps, which is why the two get used interchangeably even though the marks belong to different bodies.
Both are drawn as arcs radiating from a point, which is why they are confused. The Wi-Fi mark fans upward from a dot at the base and indicates a wireless network. The contactless mark lies on its side, opening to the right, and indicates that a card or terminal supports tap payment. Orientation is the reliable tell.