What ⌷ means
Use an APL keyboard layout or your APL editor’s symbol picker.
APL keyboards may expose specialist signs through overlays or input methods rather than ordinary letter keys; some layouts put ⌷ on a modified key.
What does ⌷ do in APL?
⌷ selects array elements with the index on the left.
In APL’s usual 1-based setup, 2⌷'ABCD' selects B. Unlike bracket indexing ('ABCD'[2]), ⌷ is an ordinary two-input function, so it composes with APL’s right-to-left expressions and tacit code (expressions written without naming intermediate results). Axis notation such as 2⌷[1]m applies the selection along axis 1 of m. J and BQN are other array languages with their own selection primitives; those are not alternate glyphs for ⌷.
Where does the name “squish quad” come from?
A 1979 APL manual records “squish quad” and .SQ.
The APL System Functions Reference Manual used .SQ as a teletype abbreviation, a text-only stand-in for the glyph. This dates documented use of the name, not the sign’s creation.
Don't confuse it with
3Questions 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 ⌷
⌷\2337Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.