A nuclear reaction in which particles produced by the fission of one atom trigger fissions of other atoms.
A series of events, each one causing or influencing the next.
A reporter's informant.
Source code.
The name of one terminal of a field effect transistor (FET).
Spring; fountainhead; wellhead; any collection of water on or under the surface of the ground in which a stream originates.
The person, place, or thing from which something (information, goods, etc.) comes or is acquired.
To obtain or procure: used especially of a business resource.
To find information about (a quotation)'s source (from which it comes): to find a citation for.