■ noun
1》 a place, person, or thing from which something originates.
↘a spring or fountain head from which a river or stream issues.
2》 a person who provides information.
↘a book or document providing evidence for research.
3》 technical a body or process by which energy or a component enters a system. The opposite of sink 2 .
■ verb obtain from a particular ~.
↘find out where to obtain.
Phrases
at ~ at the point of origin or issue.
Origin
ME: from OFr. sours(e) , past participle of sourdre 'to rise', from L. surgere .