The Geometric Shapes block, U+25A0 through U+25FF, is the Unicode standard's general-purpose collection of abstract polygons. Squares, circles, triangles, diamonds, lozenges, and their half-filled and shaded cousins all live here. The block is used for typography (bullets and dingbats), mathematics (set marks, partial-order indicators), UI design (radio buttons, fill levels, status indicators), and any text that needs a small, font-renderable shape rather than an image.
About this block
Geometric Shapes was present in the very first publication of the standard, Unicode 1.0 in October 1991. Most of the block descends from the Xerox Character Code Standard and a handful of legacy IBM PC code pages — particularly code page 437 — where line-drawing characters were used to compose tables, frames, and decorative shapes on monospaced terminals. The Unicode Consortium consolidated these legacy shapes into three contiguous blocks: Box Drawing at U+2500–U+257F for connectable line segments, Block Elements at U+2580–U+259F for solid and dithered rectangular cells, and Geometric Shapes for everything else with rotational symmetry. Later versions added Geometric Shapes Extended at U+1F780–U+1F7FF on Plane 1 (introduced in Unicode 7.0 in 2014) for the long tail of designer-supplied symbols that did not fit in the original 96-codepoint window.
Filled and outlined squares occupy the first dozen positions: ■ U+25A0 BLACK SQUARE, □ U+25A1 WHITE SQUARE, with rounded, dotted, and intersecting variants at U+25A2–U+25A9. The block then offers shaded squares ▤ ▥ ▦ ▧ ▨ ▩ — useful as quick visual percentages or for mocking up bar charts in plain text — before moving on to small black and white squares (▪ ▫), upward and downward triangles, and the four-direction pointer set ▶ ◀ ▲ ▼. The pointer set is unusual in that each direction has both a "black" filled form and a "white" outline form, and both small and large sizes. ▶ U+25B6 is the classic Play-button glyph still embedded in countless media-player UIs; ▼ U+25BC is the standard "down" caret. Circles begin at U+25CB WHITE CIRCLE and ● U+25CF BLACK CIRCLE, with quarter-circles, half-circles (◐ ◑ ◒ ◓), and the larger ◯ U+25EF LARGE CIRCLE used in many East Asian typographic conventions to highlight a kanji. The half-circles in particular doubled as the original "battery" or "fill level" indicators on early monochrome screens.
Diamonds and lozenges round out the major shape families. ◆ U+25C6 BLACK DIAMOND and ◇ U+25C7 WHITE DIAMOND are the diamond suit absent its playing-card connotations; ◈ U+25C8 WHITE DIAMOND WITH BLACK CENTER is sometimes used as a bullet in Japanese and Korean typography. ◊ U+25CA LOZENGE is a related, taller, narrower shape — beloved by mathematicians as a generic operator placeholder. The block also contains a handful of less obvious workhorses: ◯ for large rings, ◌ U+25CC DOTTED CIRCLE which renderers use as a fallback base when a combining mark would otherwise have nothing to attach to, and the half-filled triangles and pentagons that fill the long tail of the block. Filled stars are not in Geometric Shapes — ★ U+2605 and ☆ U+2606 live in the Miscellaneous Symbols block — and the ubiquitous bullet • is U+2022 BULLET, in General Punctuation. Knowing where each shape lives matters for font fallback: a missing-glyph rendering of • is much more common than a missing-glyph rendering of ●, because the latter participates in a denser, more frequently shipped block.
A subtle complication: several of these characters double as default-text emoji. ▲ ▼ ◀ ▶ and ◼ ◻ ◾ ◽ can each carry a U+FE0E text variation selector or a U+FE0F emoji variation selector. Without a selector the renderer chooses default-text presentation for the geometric-shape characters in this block (so the play button stays a flat monochrome triangle in your code editor) and emoji presentation for the few that are explicitly listed in the Unicode Emoji data files. If you ship UI built around these glyphs, set the variation selector explicitly — otherwise iOS, Android, and Windows will diverge. The General Category for the entire block is So (Symbol, other); the Bidi class is ON (other neutrals), which means embedded shapes in right-to-left text do not flip — a ▶ remains a right-pointing triangle in Arabic prose unless you mirror it yourself. For shaded fills with finer granularity, reach for Block Elements (U+2580–U+259F); for the diagrammatic outlines that connect to themselves, reach for Box Drawing. The three blocks were designed to work together, and together they cover most of the abstract-symbol needs that don't justify an image.