transitive verb

1. to bring up with care; rear
2. to help to grow or develop; stimulate; promote to foster discontent
3. to cling to in one's mind; cherish foster a hope

Etymology: ME fostren < OE fostrian, to nourish, bring up < fostor, food, nourishment < base of foda, food

adjective

1. having the standing of a specified member of the family, though not by birth or adoption, and giving, receiving, or sharing the care appropriate to that standing foster parent, foster brother
2. designating or relating to such care