1.younger brother and sister; sister-in-law; younger brother's wife
wǒ yǒusān gè dìmèi.
I have three younger siblings.
tā de dìmèi hěn kě'ài.
His younger siblings are very cute.
wǒ sān dìmèi hěn huì zuò cài.
My third younger brother's wife is good at cooking.