How to type Union
To type Union (∪), press Alt + 8746 on Windows, holding Alt while typing the digits on the numeric keypad, or write ∪ in HTML. On any system you can copy it from this page, or enter its codepoint U+222A directly: Ctrl+Shift+U then 222a on Linux, or 222a then Alt+X in Microsoft Word.
Union
- Copy it
- Unicode
- U+222A
- Windows
- Alt + 8746 needs regedit
| Where | Shortcut | How |
|---|---|---|
| Windows | Alt + 8746 | Above 255, so Windows will not accept it as typed. Copy the character instead. |
| Mac | N/A | Press the keys together. |
| HTML | ∪ | Paste this into HTML source. |
| Unicode | U+222A | UNION |
Symbols related to Union
These are filed under set in CLDR, the keyword list Unicode publishes alongside the names.
Other math symbols
∪ lives in the Mathematical Operators block (U+2200-U+22FF), the core set of mathematical and logical operators. Within Unicode it is classified as Sm, a mathematical symbol. Software may lay it out with the spacing an operator expects.
What Union is used for
In mathematical notation ∪ is a binary operator: it takes one operand on each side, and TeX sets a medium space either side of it so that the three parts read as a single expression rather than as three symbols in a row. That is the classification unicode-math gives it, and it is what decides how the symbol is set: $\cup$ in LaTeX, in maths mode rather than in a sentence.
Unicode publishes a second list of names for ∪ in CLDR, the keywords its own search data offers rather than the formal name, and they are collection and set. Those words are what somebody looking for this character is liable to type when Union is not the name they know it by, and the search on the symbol lists matches them as well as the Unicode name.
What ∪ gets confused with
Unicode's own confusables table, the one used to catch lookalike domain names, groups ∪ with U (U+0055, Latin Capital Letter U). They are separate characters that render close enough to be mistaken for one another, so a search or a string comparison will separate them where your eye will not. If Union is not matching where you expect it to, one of these is the usual reason.
What Unicode says about Union
The standard recognises ∪ under another name as well: cup. That is a formal alias, not a nickname, which is why it turns up in other people's documentation for the same codepoint.
The code chart points from ∪ to n-ary union (U+22C3). These are the characters the standard thinks you might have meant instead, which makes them the ones worth checking when Union looks nearly right but not quite.
How Union behaves in software
∪ is East Asian Ambiguous: one column in a Western locale and two in a CJK one. That is why a table that lines up on your machine can break on somebody else's, with no change to the text at all. It carries no direction of its own, so in a line that mixes English with Arabic or Hebrew it takes the direction of the text around it rather than forcing one.
What people ask about Union
What is the union symbol in math?
∪ is UNION, encoded at U+222A. It is distinct from n-ary union (U+22C3), which the chart lists beside it precisely because they are confused for one another.
Every way to write Union
| Form | Value |
|---|---|
| Codepoint | U+222A |
| Decimal | 8746 |
| UTF-8 bytes | E2 88 AA |
| UTF-16 bytes | 22 2A |
| HTML entity | ∪ |
| HTML numeric | ∪ or ∪ |
| CSS | \222A |
| JavaScript | \u222A |
| Python | \u222A |
| URL-encoded | %E2%88%AA |
| LaTeX, in maths mode | $\cup$ |
| SVG | 222A.svg · (SIL Open Font License) |
If ∪ arrives as ∪
One character has become three, which is what a three-byte UTF-8 sequence looks like when each byte is read separately: E2 88 AA read as Windows-1252 gives exactly ∪. The text is intact and the damage is in the reading, so setting the reader to UTF-8 restores it and retyping does not. A rectangle instead of the mojibake means the opposite: the encoding is right and the font has no glyph at U+222A, which for a character this far outside Latin-1 is common in older office fonts.