幺

According to Shuowen Jiezi (説文解字 shuōwén jiězì), the character is a pictograph representing a newborn baby.

There is also a theory that it is originally derived from 糸 (thread), depicting a skein of thread.

Depending on the script style, it may be written as ㄥ + ム or く + ム; either form is acceptable. This applies to all characters containing 幺.

In China, when reading out phone numbers or unit numbers, this character is used instead of 一 (one).

For example, the phone number 010 is read as 零幺零 (líng yāo líng), not 零一零 (líng yī líng), and the police number 110 is read as 幺幺零 (yāo yāo líng), not 一一零 (yī yī líng).

This is to avoid confusion because the rhyme (final sound) in the pronunciations of 1 and 7 are similar.

This is similar to Korea, where 1 and 2 have similar sounds (일, 이), so when reading phone numbers aloud, 1 and 2 are read as "하나" (one) and "둘" (two) to prevent confusion.