EXAMPLES FROM THE WEB FOR SISTER
"They needn't eat their lunch that way," declared his sister.
"But his sitting there eating in that—that shirt—" said his sister.
It's the Viluca—Mr. Bines, you know; he's bringing his sister back to me.
On his death-bed he charged his nephew to protect and cherish me as a sister.
You wouldn't turn out your sister's son, would you, Uncle Paul?
"I'll walk a bit with you," said his sister, donning her jacket and a cap.
I like him all the better for his misfortune, and so I am sure will my sister.
Then I came for her; I saved her sister; then I saw the name on the card and would not give my own.
You are going to question me, I suppose, why your sister is not thought of for Mr. Solmes?
Does not his own sister live unhappily, for want of a little of his superfluities?
mid-13c., from Old English sweostor, swuster "sister," or a Scandinavian cognate (Old Norse systir, Swedish syster, Danish søster), in either case from Proto-Germanic *swestr- (cf. Old Saxon swestar, Old Frisian swester, Middle Dutch suster, Dutch zuster, Old High German swester, German Schwester, Gothic swistar).
These are from PIE *swesor, one of the most persistent and unchanging PIE root words, recognizable in almost every modern Indo-European language (e.g. Sanskrit svasar-, Avestan shanhar-, Latin soror, Old Church Slavonic, Russian sestra, Lithuanian sesuo, Old Irish siur, Welsh chwaer, Greek eor). French soeur "a sister" (11c., instead of *sereur) is directly from Latin soror, a rare case of a borrowing from the nominative case.
According to Klein's sources, probably from PIE roots *swe- "one's own" + *ser- "woman." For vowel evolution, see bury. Used of nuns in Old English; of a woman in general from 1906; of a black woman from 1926; and in the sense of "fellow feminist" from 1912. Meaning "female fellow-Christian" is from mid-15c. Sister act "variety act by two or more sisters" is from vaudeville (1908).