Merriam-Webster Collegiate Dictionary - foster

 I. adjective  Etymology: Middle English, from Old English fostor-, from fostor food, feeding; akin to Old English foda food  Date: before 12th century affording, receiving, or sharing nurture or parental care though not related by blood or legal ties  II. transitive verb  (~ed; ~ing)  Date: 12th century  1. to give parental care to ; nurture  2. to promote the growth or development of ; encourage ~ed the college in its early years  • ~er noun FOSTER  I. biographical name Stephen Collins 1826-1864 American songwriter  II. biographical name William Zebulon 1881-1961 American Communist