Wellspring

Origin

From Middle English wellespring, from Old English wiellspring, wiellġespring ("spring, fount, fountain"), corresponding to well + spring. More at well, spring.

Full definition of wellspring

Noun

1. The source of water for a stream, spring or well; a fountainhead; a wellhead.
2. A perennial source of anything; a fountainhead of supply or emanation; resource.