What ⋈ means
It tells you to combine two relations. A relation is a data table; R ⋈ S produces row pairs according to a join rule.
A natural join matches equal values in columns with the same name; a written condition can specify another comparison, as in a theta join. E. F. Codd's 1970 paper set out the relational model that relational algebra builds on.
Don't confuse it with
1Combination ideas
1Join data relations R and S under the stated rule.
Questions people ask
1Why does ⋈ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ⋈
Windows (Word)
Alt+XType 22C8, then Alt+X to get ⋈.
Windows
Win+Rrun charmap for the full table, or use the emoji picker's Ω symbols tab (Win + .).
macOS
Control+Command+SpaceOpen the character viewer and search “bowtie”.
Linux
Ctrl+Shift+UType 22c8, then Enter or Space.
HTML
⋈CSS
\22C8LaTeX
Write `\bowtie` in math mode.
Unicode input
Enter U+22C8 with your system's character picker or Unicode input method.
Codes and encoding1 code points
HTML decimal
⋈
HTML hex
⋈
CSS content
content: "\22C8";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%8B%88
1
On screen
1
Code points
1
JS .length
3
UTF-8 bytes
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.