Diameter Symbol (⌀)

Diameter Symbol uses ⌀, U+2300 DIAMETER SIGN. It can precede a dimension in engineering notes and technical drawings, for example ⌀20 mm or a hole callout. The complete meaning depends on the drawing standard, units, tolerances, and geometry. A plain Unicode character is useful in searchable notes, but it does not replace the drafting rules that govern placement, size, and interpretation. Several characters look similar: empty set ∅, Latin Ø, and a slashed zero. Substituting one can create errors in specifications, database searches, or automated extraction. The code point should therefore be checked rather than inferred from shape. A diameter value should retain its numerical value and unit. If the document contains several circular features, labels or callout references should identify which feature is being measured. Unicode supplies the character identity. The page remains a copy-and-reference entry and does not claim that one text form satisfies every engineering standard. Examples such as ⌀20 mm, Hole: ⌀8, Shaft diameter: ⌀12.5 mm, Drawing callout: 4 × ⌀6, and Tolerance note: ⌀10 ± 0.1 mm define the operational range of Diameter Symbol. The Diameter Symbol use cases are technical drawings, specifications, engineering labels, and unicode references, not unrelated image, logo, or broad-symbolism queries. Keep units and tolerances with the dimension. Follow the applicable technical drawing standard. For Diameter Symbol, Unicode, W3C/WCAG, and WHATWG HTML provide the evidence base, while diameter and Diameter Sign remain accepted lookup labels.