妹妹

妹 mèi HSK 1 #3,266

younger sister

兄妹 xiōngmèi #7,972

brother and sister (specifically older brother and younger sister) / siblings (male and female)

表妹 biǎomèi #8,028

younger female cousin (on the maternal side, or father's sister's side) / younger female cousin with a different surname

姐妹 jiěmèi HSK 4 #1,929

sisters / close female friends; besties

姊妹 zǐmèi #13,092

sisters (older and younger) / sister (as in sister city, sister school)

弟弟 dìdi HSK 1 #918

younger brother

姐姐 jiějie HSK 1 #1,112

older sister

弟妹 dìmèi #26,132

younger siblings / younger brother and younger sister / younger brother's wife (sister-in-law)

没有 méiyǒu HSK 1 #48

to not have / there is not / did not (negating past action)

没 méi HSK 1 #32

have not; not