"Uncle's wife" in Engpsh is referred to as "aunt".

The word "aunt" has its origins in the Old French word "ante" which was a variation of the Latin word "amita" meaning "father's sister." Over time, the word evolved to mean the wife of one's uncle.

Example sentences:

My aunt is visiting from out of town.
(我的姑妈从外镇来看望我们。)
I haven't seen my aunt in years.
(多年没见我的姑妈了。)
I'm going to my aunt's house for dinner.
(我要去我姑妈家吃晚饭。)