Down tack (⊤) is the Unicode character at U+22A4 in Mathematical Operators. Official name: DOWN TACK. It looks like a T (bar on top) and is often used for tautology or the top element in logic and order theory.
Remember
Character ⊤
Unicode U+22A4
Named entity ⊤
Hex entity ⊤
Decimal ⊤
CSS escape \22A4
Not the same ⊥ (⊥) · ⊢ (⊢) · ⊣ (⊣)
Prefer ⊤ in HTML markup (also aliased as ⊤). You can also type ⊤ in UTF-8, or use numeric forms when needed.
Built with Named: ⊤
Built with Hex: ⊤
Built with Decimal: ⊤
Built with CSS: ⊤
Typed: ⊤
Label: Tautology ⊤
How It Works
1. Named:⊤ is the preferred HTML5 name for U+22A4 → ⊤ (alias: ⊤).
2. Hex / decimal:⊤ and ⊤ insert the same code point.
3. CSS: use \22A4 in content (not an HTML entity). #point::after appends ⊤.
4. Typed: paste ⊤ in a UTF-8 document, or pair it with a label like Tautology ⊤.
Pitfalls & Tips
Common mistakes when working with Down Tack.
Opposite
Not ⊥ / ⊥
⊥ and ⊥ are ⊥ (U+22A5, up tack). ⊤ is ⊤ (U+22A4).
Name
Unicode vs math nickname
Unicode calls it DOWN TACK, but HTML names it ⊤ because the glyph is the math “top” symbol.
Diacritic
Not combining U+031E
U+031E is a combining mark below a letter. U+22A4 is a standalone symbol.
CSS vs HTML
Do not mix escapes
\22A4 belongs in CSS strings. ⊤ / ⊤ belong in HTML.
Fonts
Math font coverage
Some fonts omit Mathematical Operators glyphs. Prefer a font with solid math coverage.
a11y
Add accessible text
A lone tack can be unclear to screen readers. Pair it with visible text or an aria-label.
Semicolon
End references
Always finish entities with ; — write ⊤, not &top.
Compatibility
Browser Support
Down tack (U+22A4) and its entity forms (⊤, ⊤, ⊤, CSS \\22A4) are supported in all mainstream browsers. Visible glyphs depend on Mathematical Operators font coverage.
✓ Universal support
Down Tack (⊤)
Encode with named, hex, decimal, CSS escape, or type the character — same code point everywhere encoding is supported.
100%Browser coverage
Google ChromeSupported
Yes
Microsoft EdgeSupported
Yes
Mozilla FirefoxSupported
Yes
Apple SafariSupported
Yes
OperaSupported
Yes
Internet ExplorerAll versions
Yes
U+22A4 / ⊤Full support
Bottom line: Prefer ⊤ (or ⊤) in HTML. Use ⊤ / ⊤ when numeric form is required, and \\22A4 only inside CSS content.
Remember
Key Takeaways
Unicode: down tack is U+22A4 (decimal 8868) — glyph ⊤.
HTML: prefer ⊤ (alias ⊤).
CSS: use \22A4 inside content for generated text.
Opposite:⊤ (⊤) ≠ ⊥ / ⊥ (⊥).
One line:U+22A4 → ⊤ / ⊤ / CSS \22A4.
Frequently Asked Questions
Use ⊤ (named), ⊤ (hex), ⊤ (decimal), type ⊤ directly in UTF-8, or the CSS escape \22A4 in content. Prefer ⊤ or ⊤ in normal HTML.
U+22A4 (DOWN TACK). Hex 22A4, decimal 8868. It belongs to the Mathematical Operators block (U+2200–U+22FF).
Yes. Use ⊤ or ⊤. Numeric forms ⊤ and ⊤ also work. The opposite up tack uses ⊥ / ⊥ / ⊥ (U+22A5).
Use it for tautology, lattice top, or similar formal notation. Prefer ⊥ for up tack / bottom / perpendicular, and combining U+031E when you need a down-tack diacritic below a letter.
HTML entities (⊤, ⊤, or ⊤) go in markup. The CSS escape \22A4 goes in stylesheet strings (usually content on ::before/::after).
No. ⊤ is ⊤ (U+22A4, down tack). ⊥ and ⊥ are ⊥ (U+22A5, up tack). They are opposite glyphs.
🤔
Did you know?
Down tack is Unicode U+22A4 (decimal 8868) — glyph ⊤ (DOWN TACK) in Mathematical Operators. HTML5 names it ⊤ (also ⊤). In logic it often means tautology or the top element. The opposite up tack is ⊥ / ⊥ (⊥).
