Definition of fosters:
(v) :
(transitive) To nurture or bring up offspring, or to provide similar parental care to an unrelated child.
(v) :
(transitive) To promote the development of something; to cultivate and grow a thing.
(n) :
(uncountable) The care given to another; guardianship.
(n) :
(countable, informal) A foster parent.
(adj) :
Providing parental care to children not related to oneself.
(adj) :
Receiving such care.