source

noun

1. The person, place, or thing from which something (information, goods, etc.) comes or is acquired.

   “The accused refused to reveal the source of the illegal drugs she was selling.”

   “More than a mere source of Promethean sustenance to thwart the cold and cook one's meat, wood was quite simply mankind's first industrial and manufacturing fuel.”

   “Investors face a quandary. Cash offers a return of virtually zero in many developed countries; government-bond yields may have risen in recent weeks but they are still unattractive. Equities have suffered two big bear markets since 2000 and are wobbling again. It is hardly surprising that pension funds, insurers and endowments are searching for new sources of return.”

2. Spring; fountainhead; wellhead; any collection of water on or under the surface of the ground in which a stream originates.

   “The main sources of the Euphrates River are the Karasu and Murat Rivers.”

   “Most of the Himalayan rivers have been relatively untouched by dams near their sources. Now the two great Asian powers, India and China, are rushing to harness them as they cut through some of the world's deepest valleys.”

3. A reporter's informant.
4. Source code.
5. The name of one terminal of a field effect transistor (FET).
6. A node in a directed graph whose edges all go out from it; one with no entering edges.
7. The domain of a function; the object which a morphism points from.

   “Coordinate term: target”

verb

1. To obtain or procure: used especially of a business resource.

   “But the point when it would have to look at alternative new-build vehicles was always looming large, and there would inevitably be a finite number of Class 66s it could source from elsewhere, and a limit to other locomotives it could re-power.”

2. (transitive)To find information about (a quotation)'s source (from which it comes): to find a citation for.