Arrows Block

The Arrows block (U+2190–U+21FF) contains 112 code points representing directional arrows in a systematic variety of weights, styles, and orientations. Arrows appear in mathematics, logic, programming documentation, user interface design, and everyday writing, making this one of the more frequently used symbol blocks outside the Basic Latin range.

Core Directional Arrows

The block begins with four simple arrows pointing in the cardinal directions:

These are followed by bidirectional and all-direction variants:

Double and Heavy Arrows

Double-stroke arrows have distinct meaning in formal logic and mathematics:

The distinction between single arrow (→) and double arrow (⇒) matters in mathematics: → typically denotes a function (f: A → B) or a mapping, while ⇒ denotes logical implication. Similarly, ↔ suggests a correspondence or bijection while ⇔ is the biconditional.

Arrows in Mathematics

Arrows encode a wide range of mathematical relationships:

• U+21A6 RIGHTWARDS ARROW FROM BAR ↦ — maps-to notation: x ↦ x² defines a function mapping
• U+21A0 RIGHTWARDS TWO HEADED ARROW ↠ — surjective (onto) function
• U+21A3 RIGHTWARDS ARROW WITH TAIL ↣ — injective (one-to-one) function
• U+21CC RIGHTWARDS HARPOON OVER LEFTWARDS HARPOON ⇌ — chemical equilibrium
• U+21BC LEFTWARDS HARPOON WITH BARB UPWARDS ↼ and U+21C0 RIGHTWARDS HARPOON WITH BARB UPWARDS ⇀ — used in chemistry and physics for half-reactions and spin states
• U+21DD RIGHTWARDS SQUIGGLE ARROW ⇝ — leads to, reduces to (in rewriting systems)
• U+21AF DOWNWARDS ZIGZAG ARROW ↯ — contradiction (some proof styles)

Arrows in Programming and Documentation

Arrows are ubiquitous in technical writing:

• → in API documentation to indicate a function's return type: parse(str) → int
• ⇒ in pattern matching and case analysis: case 0 ⇒ "zero"
• ← in assignment (some functional programming notations)
• ↑ and ↓ in data structure descriptions for links (parent/child nodes, call stack)
• ⤴ (U+2934) and ⤵ (U+2935) for "back to top" and "continue below" navigation hints

Arrows in User Interface Design

Arrows communicate navigation and action affordances throughout UI design:

• Pagination: ← Previous / Next →
• Carousel controls: ‹ and › (or ← →)
• Expand/collapse: ▲ (up = collapse) / ▼ (down = expand)
• Breadcrumb separators: Home › Category › Page
• Sort indicators: ↑ ascending / ↓ descending
• Undo/redo: ↩ (U+21A9 LEFTWARDS ARROW WITH HOOK) / ↪ (U+21AA)
• Return/enter key: ↵ (U+21B5 DOWNWARDS ARROW WITH CORNER LEFTWARDS)

Supplemental Arrow Blocks

The main Arrows block is supplemented by three additional blocks for arrows that didn't fit:

Notable additions from Supplemental Arrows-A include: - U+27F6 LONG RIGHTWARDS ARROW ⟶ — for longer mappings in commutative diagrams - U+27FA LEFT RIGHT DOUBLE ARROW ⟺ — long biconditional - U+27F9 RIGHTWARDS DOUBLE ARROW ⟹ — long implication

Emoji Overlap

Several arrow emoji were added to Unicode outside the Arrows block:

• ▶ (U+25B6) PLAY button — triangular right-pointing arrow
• ⬅ (U+2B05), ⬆ (U+2B06), ⬇ (U+2B07) — emoji-styled arrows with default emoji presentation
• 🔄 (U+1F504) — counterclockwise arrows (refresh/reload)
• ↩ (U+21A9) and ↪ (U+21AA) — reply/forward conventions in email and messaging

The difference in rendering: characters in the Arrows block default to text presentation (rendered in the font's glyph style) while certain characters have emoji presentation sequences (VS16, U+FE0F) that trigger colorful emoji rendering on mobile platforms.