foster

Etymology 1

From Middle English foster, from Old English fōstor (“food, sustenance”), from Proto-West Germanic *fōstr, from Proto-Germanic *fōstrą (“nourishment, food”). Cognate with Middle Dutch voester (“nursemaid”), Middle Low German vôster (“food”), Old Norse fóstr (“nurturing, education, alimony, child support”), Danish foster (“fetus”), Swedish foster (“fetus”).

adj

1. Providing parental care to children not related to oneself.
   foster parents
2. Receiving such care.
   a foster child
3. Related by such care.
   We are a foster family.

noun

1. (countable, informal) A foster parent.
   Some fosters end up adopting.
2. (uncountable) The care given to another; guardianship.

verb

1. (transitive) To nurture or bring up offspring, or to provide similar parental care to an unrelated child.
   Some ſay that Rauens foſter forlorne children, / The whilſt their owne birds famiſh in their neſts: / Oh be to me though thy hard hart ſay no, / Nothing ſo kinde but ſomething pittiful. c. 1588–1593, [William Shakespeare], The Most Lamentable Romaine Tragedie of Titus Andronicus: As It was Plaide by the Right Honourable the Earle of Darbie, Earle of Pembrooke, and Earle of Sussex Their Seruants (the First Quarto), London: Printed by Iohn Danter, and are to be sold by Edward White & Thomas Millington, at the little North doore of Paules at the signe of the Gunne, published 1594, →OCLC, [https://books.google.com/books?id=4XcWAAAAYAAJ&pg=PP37 [Act II, scene iii]]
2. (transitive) To cultivate and grow something.
   Our company fosters an appreciation for the arts.
   Grimsby doesn't ever wound quite as devastatingly as Borat or Brüno, but it's a vital, lavish, venomously profane two fingers up at Benefits Street pity porn and the social division it fosters. 23 February 2016, Robbie Collin, “Grimsby review: ‘Sacha Baron Cohen’s vital, venomous action movie’”, in The Daily Telegraph (London)
3. (transitive) To nurse or cherish something.
4. (intransitive, obsolete) To be nurtured or trained up together.

Etymology 2

noun

1. (obsolete) A forester.