The perpendicular sign ⊥ states that two lines meet at a right angle, as in AB ⊥ CD. Type 22A5 then Alt+X in Word. Unicode names this character the up tack, because logic uses the same glyph to mean falsity or the bottom element.
01 All shortcuts at a glance
| Platform | Shortcut | |
|---|---|---|
| Windows (any app) | Win+. or Win+; emoji/symbol picker, or Character Map (Win+R → charmap) |
|
| Mac | Control+Command+Space to open Character Viewer, search "Up Tack" |
|
| Word / Outlook | Type 22A5, then press Alt+X |
|
| Linux (IBus) | Ctrl+Shift+U, then 22a5, then Enter |
|
| HTML / CSS | ⊥ · \22a5 (CSS) |
02 Step by step, per platform
A real, followable procedure for every platform, not a thin restatement of the shortcut.
Windows
- Open Character Map: Win+R, type charmap, press Enter.
- Search or scroll for Up Tack (U+22A5).
- Select it, click Copy, then paste where you need it.
Mac
- Press Control+Command+Space to open the Character Viewer.
- Type "Up Tack" in the search field.
- Double-click the result to insert it.
Microsoft Word
- Type 22A5.
- Press Alt+X immediately after, it converts the hex code to ⊥.
03 Characters in this set
04 Troubleshooting & confusables
| Looks like it | But it's actually | When to use |
|---|---|---|
| ⊤ (U+22A4) | Down tack, the inverted form | In logic it means truth or the top element. Not a geometric relation. |
| ⟂ (U+27C2) | Perpendicular, a separate encoded character | A dedicated geometry character. U+22A5 is the more widely supported one. |
| T upside down | A rotated Latin letter | Never. Use the encoded character so it copies and reads correctly. |
05 FAQ
What is the Unicode code point for the perpendicular sign?
The commonly used character is U+22A5, decimal 8869, named UP TACK. A dedicated PERPENDICULAR character also exists at U+27C2.
Why is it called the up tack?
Because the same glyph serves logic, where it denotes falsity or the bottom element of a lattice. Unicode named it for that role, and geometry borrowed the shape.
Which character should I use?
U+22A5 in practice. It has far wider font support and is what most equation editors insert. U+27C2 is more precise semantically but less reliably rendered.
What does ⊥ mean in logic?
Falsity, the proposition that is never true, and by extension the bottom element of an ordered structure. Its mirror ⊤ denotes truth.
Is it used for vectors?
Yes. Two vectors are written as perpendicular when their dot product is zero, and the same symbol marks orthogonality in linear algebra.