In Mandarin Chinese, 乌 (Pinyin: wū 🔊 or wù 🔊) is either a noun meaning “crow”, “raven”, or “rook”, or an adjective for colour “black”. It looks like this latter meaning arose as a short for 乌黑, “black as a crow” (or a raven, or a rook, in Chinese it’s all the same).
乌 is a simplified form of the traditional character 烏, which evolved from a pictogram of a bird, just like 马 (remember it?) is a simplified form of 馬. Now to remember the difference between a crow and a horse...
Compounds of 乌 include
- 乌 + 木 = 乌木 (wūmù): ebony
- 乌 + 金 = 乌金 (wūjīn): “black gold”: ink or coal
- 乌 + 龙 + 茶 = 乌龙茶 (wūlóngchá): oolong tea (literally, “black dragon tea”)