The intersection sign ∩ gives the elements two sets have in common, so A ∩ B holds only what is in both. Type 2229 then Alt+X in Word. The opening faces down, which is the reliable way to tell it from union. It is sometimes read as "cap".
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 "Intersection" |
|
| Word / Outlook | Type 2229, then press Alt+X |
|
| Linux (IBus) | Ctrl+Shift+U, then 2229, then Enter |
|
| HTML / CSS | ∩ · \2229 (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 Intersection (U+2229).
- Select it, click Copy, then paste where you need it.
Mac
- Press Control+Command+Space to open the Character Viewer.
- Type "Intersection" in the search field.
- Double-click the result to insert it.
Microsoft Word
- Type 2229.
- 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+222A) | Union, opening upward | The opposite operation, combining everything from both sets. |
| n as a letter | The Latin letter n | A handwritten substitute. The real symbol is symmetrical with no descender. |
| ⋂ (U+22C2) | N-ary intersection | The large operator for intersecting a whole family of sets. |
05 FAQ
What is the Unicode code point for intersection?
It is U+2229, decimal 8745. There is no Windows Alt code for it.
How do I remember which way it opens?
Intersection looks like a cap or an arch, holding only what sits under both sets. Union looks like a cup, open to receive everything from both.
What if two sets share nothing?
Their intersection is the empty set, written ∅ at U+2205. Such sets are called disjoint.
What is the large version for?
U+22C2 is the n-ary intersection, used with an index to intersect a whole indexed family at once, in the same way ∑ generalises addition.
Does it relate to logical and?
Yes, closely. Membership in A ∩ B holds exactly when membership in A and membership in B both hold, which is why ∧ and ∩ mirror each other.