妈妈的妹妹在英语中称为 "Aunt"。
"Aunt" 是英语中表示 "姑妈" 的词汇，来源于古英语 "æmette" 或 "æmestre"，意思是 "伯母、姑母或其他父亲兄弟姐妹的妻子"。
例句1:
My aunt is visiting from out of town.
(我姑妈从外地来看我)
例句2:
My aunt is my mom's sister.
(我姑妈是我妈妈的妹妹)
例句3:
I have to go to my aunt's house for dinner tonight.
(今晚我要去姑妈家吃饭)