Square kiro

㌔ means Japanese キロ, the short form “kilo.”

With a distance, it means kilometres; with a weight, kilograms. The Japanese word キロ is documented by 1877, and its shortened use by 1909. Related Japanese-made unit kanji such as 粁 and 瓩 were reported from the 1890s; they were parallel solutions, not proven ancestors of ㌔.

For ㌔ itself, the computer-era record shows a typographic purpose. Japan’s JIS C 6226 character standard was established in 1978. NEC, a Japanese computer maker, included ㌔ in row 13 of its character set; JIS X 0213 listed it as a one-cell form in 2000. The compact shape solved a layout problem, not a unit problem.

㌔ saves a character cell; it does not change the unit

In Japanese text layout, characters can sit in square cells. Ordinary キロ uses two positions; ㌔ packs the same two katakana into one square. Other compact Japanese unit forms include ㌢, ㍍, and ㌘; ㌖ writes キロメートル in the same style.

Compatibility normalization can expand ㌔ to キロ: the reading survives, but the boxed styling does not. A device whose font lacks this character may show an empty box. For text that needs to display reliably, ordinary キロ or a spelled-out unit is safer.