唯一
wéiyī · HSK 5
sole
☝️ 唯 wéi = only + 一 yī = one → the one and only
唯 carries the sense of 'only/just' and 一 means 'one', so 唯一 literally stacks 'only' + 'one' to mean sole or unique. The 口 radical in 唯 hints at a spoken affirmation — a single yes.
唯 — mouth 口 + short-tailed bird 隹
A semantic-phonetic compound: 口 (mouth) gives the meaning related to speech or response, while 隹 (short-tailed bird) supplies the sound. Originally meant 'to answer' or an affirmative reply, later extended to 'only' or 'alone'.
一 — single horizontal stroke
一 is one of the simplest pictographs in Chinese, depicting a single horizontal line to represent the number one. It has retained essentially the same form since oracle bone script over 3,000 years ago. By extension it also means 'first,' 'whole,' or 'same.'