What ⃐ means
Put it after the character it should modify.
In Unicode text, the left harpoon accent is a nonspacing combining mark: it takes its position from the preceding character instead of occupying a separate cell. In TeX math, \leftharpoonaccent accents one symbol; \overleftharpoon stretches over a longer expression.
What does this mark mean in a formula?
It marks the attached quantity as a vector.
Vector notation developed through the nineteenth century as mathematicians worked out how to write vectors. Hamilton, Grassmann, and Gibbs used different conventions; Gibbs’s notation reached wider use through Edwin Wilson’s 1901 textbook.
Technical and specialized; it belongs in equations, math typesetting, and source files.
Alone, it is not a left arrow; it needs a base character and a font that positions it.
Don't confuse it with
3Questions people ask
2Why does this mark look wrong?
The font is usually the issue: a fallback font may lack instructions for positioning combining marks, making the harpoon drift, vanish, or shift spacing. Try a font with math accent positioning.
Can I use it as a normal left arrow?
No. It modifies a preceding character; use a dedicated left arrow when direction itself is the message.
How to type ⃐
⃐\20D0Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.