Emily Dickinson Lexicon

FOS'TER, v.t. [Sax. fostrian, from foster, a nurse or food; Sw. and Dan. foster, a child, one fed; Dan. fostrer, to nurse. I suspect this word to be from food, quasi, foodster, for this is the D. word, voedster, a nurse, from voeden, to feed; D. voedsterheer, a foster-father.]

1. To feed; to nourish; to support; to bring up. Some say that ravens foster forlorn children. Shak.
2. To cherish; to forward; to promote growth. The genial warmth of spring fosters the plants.
3. To cherish; to encourage; to sustain and promote; as, to foster passion or genius.