Meaning

noun a female person who has the same parents as another person

noun (Roman Catholic Church) a title given to a nun (and used as a form of address)

noun a female person who is a fellow member of a sorority or labor union or other group

originEtymology tree Proto-Indo-European *swé Proto-Indo-European *h₁ésh₂r̥ Proto-Indo-European *su-h₁ésh₂-ōr? Proto-Indo-European *swé Proto-Indo-European *-sōr ? Proto-Indo-European *swésōrder. Proto-Germanic *swestēr Proto-West Germanic *swester Old English sweostor Middle English suster English sister Inherited from Middle English suster, from Old English sweostor, from Proto-West Germanic…

Etymology from Wiktionary, CC BY-SA 3.0