I. ˈfȯs-tər, ˈfäs- adjective
Etymology: Middle English, from Old English fōstor-, from fōstor food, feeding; akin to Old English fōda food
Date: before 12th century
: affording, receiving, or sharing nurture or parental care though not related by blood or legal ties
II. transitive verb
( fos·tered ; fos·ter·ing -t(ə-)riŋ)
Date: 12th century
1. : to give parental care to : nurture
2. : to promote the growth or development of : encourage
foster ed the college in its early years
• fos·ter·er -tər-ər noun