source

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A person or thing from which something comes into being or is derived or obtained.
• noun The point of origin of a stream or river. synonym: origin.
• noun One, such as a person or document, that supplies information.
• noun Physics The point or part of a system where energy or mass is added to the system.
• transitive verb To specify the origin of (a communication); document.
• transitive verb To obtain (materials or parts) from another business, country, or locale for manufacture.
• transitive verb To outsource or insource (tasks or jobs, for example).

from The Century Dictionary.

• noun A rising; a rise; a soaring.
• noun A spring; a fountainhead; a wellhead; any collection of water on or under the surface of the ground in which a stream originates.
• noun A first cause; an origin; one who or that which originates or gives rise to anything.
• To rise, as a hawk; swoop; in general, to swoop down; plunge; sink; souse. See souse.
• To spring; take rise.
• To plunge down; souse.
• noun In geometry, a place of transition from space of n ± 1 into space of n dimensions.
• noun In electricity: That point or region in an electric circuit at which abrupt difference of potential exists so that current flows from it on one side through the circuit and toward it through the circuit from the other side. Thus a dynamo generator, a voltaic cell, or a charged condenser is a source of current in the circuit in which they are placed.
• noun In the case of current flow in plane sheets, a point at which the current enters the sheet.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete The act of rising; a rise; an ascent.
• noun The rising from the ground, or beginning, of a stream of water or the like; a spring; a fountain.
• noun That from which anything comes forth, regarded as its cause or origin; the person from whom anything originates; first cause.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The person, place, or thing from which something (information, goods, etc.) comes or is acquired.
• noun Spring; fountainhead; wellhead; any collection of water on or under the surface of the ground in which a stream originates.
• noun A reporter's informant.
• noun computing Source code.
• noun electronics The name of one terminal of a field effect transistor (FET).
• verb To obtain or procure: used especially of a business resource.
• verb transitive To find information about (a quotation)'s source (from which it comes): to find a citation for.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (technology) a process by which energy or a substance enters a system
• verb get (a product) from another country or business
• noun a person who supplies information
• noun anything (a person or animal or plant or substance) in which an infectious agent normally lives and multiplies
• noun a publication (or a passage from a publication) that is referred to
• verb specify the origin of
• noun the place where something begins, where it springs into being
• noun a facility where something is available
• noun anything that provides inspiration for later work
• noun someone who originates or causes or initiates something
• noun a document (or organization) from which information is obtained