What ⎤ means
It forms the upper-right corner of a tall square bracket.
When a mathematical expression needs more vertical room, typesetting joins ⎤ to a vertical middle segment and lower corner to build the bracket's right side.
Don't confuse it with
1Questions 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 23A4, 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 “right square bracket upper corner”.
Linux
Ctrl+Shift+UType 23a4, then Enter or Space.
HTML
⎤CSS
\23A4Codes and encoding1 code points
HTML decimal
⎤
HTML hex
⎤
CSS content
content: "\23A4";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%8E%A4
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.