CJK Unified Ideograph-7C8D

It means one millimetre: 0.001 metre. In Japanese, read it as ミリメートル. 米 supplies metre and 毛 supplies one-thousandth, so 粍 is a compact unit formula, not a picture.

Japan seriously introduced metric measurement through 西洋度量考 in 1855; the 度量衡法 took effect in 1893 alongside 尺貫法. ミリメートル was long to repeat, so one character fit technical print. A 1899 metrology handbook documents the system.

Some accounts place Central Meteorological Observatory use in 1891. A historical-metrology review says the evidence does not establish one inventor, so 1891 is a reported milestone, not a secure birth date.

Why do Chinese readings differ?

The unit is shared, but the usual written name changes. Japanese references read 粍 as ミリメートル. Taiwan's 2024 Ministry of Education dictionary records lí and the Chinese forms 公釐, 釐米, and 毫米. Readers may recognize the unit without using the Japanese reading.

Its Japanese relatives are 糎 for centimetre, 粁 for kilometre, and 米 for metre. They share one build: 米 marks the base and the other part marks scale. Chinese notation commonly uses multi-character forms such as 厘米 or 公里.

Should I write 粍 or mm?

Use mm for new technical writing; keep 粍 for quoted Japanese text.

A number before 粍 is a measurement: 5粍 means five millimetres. Older Japanese scientific and literary text also uses forms such as 一・五粍; mm is clearer across languages and fonts.