What ㌾ means
It can mean volt or bolt: the Japanese word ボルト.
Japanese katakana, a script often used for borrowed words, spells both meanings as ボルト; context distinguishes the electrical unit from the threaded fastener.
Why is ㌾ square?
It gives that spelling one full character-width box.
Unicode retains square forms for compatibility with East Asian character sets; modern Japanese layout can give ordinary katakana the same box. Unicode 1.1 encoded ㌾ in 1993; that is the encoding date, not the word’s origin.
The unit is named for physicist Alessandro Volta. A Paris congress on electricity recognized the volt as a practical unit in 1881.
Don't confuse it with
4Questions people ask
1Does ㌾ look the same in every font?
No. Unicode’s chart glyph is a reference, not a fixed drawing; fonts may shape the square differently while keeping the character’s identity.
How to type ㌾
㌾\333ECodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.