About Rightwards Arrow With Hook Right Arrow With Hook
Rightwards Arrow With Hook Right Arrow With Hook is the Unicode character ↪ at codepoint U+21AA in the Arrows block of the Basic Multilingual Plane (BMP).
Reference
The mirror of the leftward hooked arrow, and it shares its unusual profile: general category So rather than Sm, East Asian Width Neutral, line-break class AL, and Other_Math in PropList — which is what gives a non-Sm character the derived Math property. Unicode's math-class table files it as a relation. Emoji since version 0.6 but not Emoji_Presentation, so it renders as text until a variation selector asks otherwise. Two HTML names, both mathematical. No chart annotation. Its mathematical reading is the one it is actually used for: an embedding or an injection, written f : X ↪ Y and read "hooks into".
Typical uses
- Injections and embeddings in mathematics: f : X ↪ Y
- Reply, forward and "go to" affordances in interfaces
- The soft line break, in editors that show one
- With a variation selector, the left-arrow-curving-right emoji
At a glance
- U+21AA, Arrows; Unicode 1.1 (1993); general category So
- East Asian Width Neutral; line break class AL; Bidi_Mirrored No
- HTML: ↪, ↪
- Emoji since E0.6, text by default; no Windows-1252 slot
Historical Notes
Origins
The hooked arrow is a notation for a map that does not collide — the hook is the picture of one set being slotted into another. The interface use borrowed the shape wholesale, because the same curve reads as a line returning or a message being sent back.
Unicode
Unicode 1.1, released in 1993, in the Arrows block, with no annotation, alias or cross-reference in the chart. Its mathematical standing is recorded in PropList rather than in the character name: Other_Math, and from there the derived Math property.
The two readings
Wikipedia's article on embeddings names the character explicitly — "the use of a 'hooked arrow' (U+21AA ↪ RIGHTWARDS ARROW WITH HOOK); thus: f : X ↪ Y" — and adds that some authors reserve the notation for inclusion maps specifically. Its article on injective functions gives both this arrow and U+21A3 as the specialised notation. The interface reading has no comparable written standard; it is convention.
Developer Notes
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How to Use Rightwards Arrow With Hook Right Arrow With Hook
To use the Rightwards Arrow With Hook Right Arrow With Hook symbol (↪) in HTML, insert the
entity ↪ directly into your markup. The decimal entity ↪ works in any HTML-serialised document.
In CSS pseudo-elements use content: '\21AA';.
In JavaScript and TypeScript the escape '\u21AA' evaluates to ↪. In Python source, write '\u21AA'.
The character encodes to E2 86 AA as UTF-8 bytes and 21AA as UTF-16 code units. Its decimal codepoint is 8618.
This is a text-based Unicode character. It will render in the current font on most platforms. If a font lacks this glyph, the browser may show a placeholder or fall back to a system font.
Things to know
- General category So, not Sm. Branch on the derived Math property, not on the category, or you will misclassify it.
- Emoji but not Emoji_Presentation. Bare, it is monochrome; with U+FE0F it becomes the coloured button.
- East Asian Width Neutral and line-break class AL, so one terminal cell in any locale — unlike the Sm arrows around it, which are Ambiguous.
- Do not approximate the hook with a lowercase r or a bracket. The single character carries its meaning to a screen reader; a hand-built lookalike does not.
- Pattern_Syntax applies; no Windows-1252 slot; stable under all four normalisation forms.
In the Wild
Unlike its leftward twin, some of this character's use is genuine. On 5 August 2026 Wikipedia's article on injective functions carried three occurrences in running notation: "often denoted by using the specialized arrows ↣ or ↪ (for example, f : A ↣ B or f : A ↪ B), although some authors specifically reserve ↪ for an inclusion map". The article on embeddings carried two, naming the codepoint outright. Four more are chart specimens on the article about the Arrows block.
So the pattern is the opposite of what the character's interface fame suggests: where it appears in text at all, it is doing mathematics. The interface reading lives in icons, which reading text cannot see. Pages change; this is what those showed on the day.
FAQ
What does the hook mean?
In mathematics, an injection or an embedding — a map that slots one set into another without collisions.
Is it the reply icon?
Interfaces use the shape for reply and forward. Nothing in the character says so; that meaning is convention, and it is drawn far more often than it is typed.
Why is it not a maths symbol by category?
Unicode files it as So. Its mathematical standing comes from Other_Math in PropList, which produces the derived Math property.
Does it have an emoji form?
Yes, from emoji version 0.6, but only with a following variation selector. On its own it stays text.