What ഉ means
It marks Malayalam's short u sound.
The independent Malayalam u begins a syllable; after a consonant, dependent sign ു adds the same vowel. Say it briefly, like the u in Spanish luna.
The Vazhappally plates (882–3 CE) preserve an early Malayalam record in Vatteluttu, an older rounded script. Malayalam also drew on Grantha, a script used for Sanskrit, to write Sanskrit loanwords. A 1971 reform unified older consonant-specific u signs for print; by 2018, traditional and reformed shapes appeared in handwriting and public lettering.
Don't confuse it with
1Questions people ask
1Why does ഉ 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 ഉ
ഉ\0D09Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.

