Black

I was using some black pepper yesterday and I thought why was it called hêg4 hou5zio1 黑胡椒 and I was also thinking why daylight robbery or a protection racket or a shop which robs its customers call hêg4diam3 黑店 and when the truth is distorted, like the way the US invents fake stories about China, is called diang1dao2hêg4bêh8 顛倒黑白 ?

What has happened to the ou1 烏 for black?

When the sky and earth are both dark, we do call this ou1tiⁿ1 am3di7 烏天暗地 and when someone is beaten until blue-black, we do call this bruise ou1cêⁿ1 烏青 and the most famous ou1 is used in black dragon tea and we call this oolong tea as ou1lêng5 dê5 烏龍茶 and black olives as ou1nam2 烏欖 and freshwater eel as ou1hiⁿ6muaⁿ5 烏耳鰻｜乌耳鳗

Therefore, we do say hêg4 and ou1 for black.

烏耳鰻