What ⌡ means
The 1981 IBM PC character set stored ⌠ and ⌡ separately; a vertical box-drawing line between them could make a taller integral. In math fonts, ⎮ is a middle extension.
Leibniz wrote the complete sign ∫ in 1675, adapting the old elongated letter s, the first letter of Latin summa (“sum”). ⌡ came later as a computer-typography piece.
Why can the pieces look misaligned?
The font must align each part. Different math fonts can leave gaps or shifts at the joins. A font that supports integral assembly may align them better.
Don't confuse it with
4Questions 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 2321, 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 “bottom half integral”.
Linux
Ctrl+Shift+UType 2321, then Enter or Space.
HTML
⌡CSS
\2321Windows
Try Alt+2321 with Unicode Alt input; Alt+245 is a legacy code-page route.
Codes and encoding1 code points
HTML decimal
⌡
HTML hex
⌡
CSS content
content: "\2321";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%8C%A1
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.