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ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.foster-sister - your foster sister is a female who is not a daughter of your parents but who is raised by your parents
female person, female - a person who belongs to the sex that can have babies
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.


(ˈfostə) verb
1. to look after for a period of time; to bring up a child that is not one's own. She fostered the children for several months.
2. to encourage or give help to (ideas etc). She fostered the child's talents.
ˈfoster-brother, ˈfoster-sister nouns
a child that has been fostered in another child's family.
ˈfoster-child noun
a child fostered by a family.
ˈfoster-parent (ˈfoster-father/ˈfoster-mother) noun
a person who looks after a child not his or her own.
Kernerman English Multilingual Dictionary © 2006-2013 K Dictionaries Ltd.
References in classic literature ?
The proud consciousness of her trust, and the great importance she derived from it, might have advertised it to all the house if she had had to run the gauntlet of its inhabitants; but as Dolly had played in every dull room and passage many and many a time, when a child, and had ever since been the humble friend of Miss Haredale, whose foster-sister she was, she was as free of the building as the young lady herself.
I had not the heart to leave my charge; and besides, you know, I had been his foster-sister, and excused his behaviour more readily than a stranger would.
Needless to say that one of the first things his mother told him was the sad condition of the princess, his foster-sister. Marzavan asked if she could not manage to let him see the princess without the king's knowledge.