n.
1.the source from which something derives (i.e. comes or issues)
2.(historical linguistics) an explanation of the historical origins of a word or phrase
3.a line of reasoning that shows how a conclusion follows logically from accepted propositions
4.(descriptive linguistics) the process whereby new words are formed from existing words or bases by affixation: `singer' from `sing'
5.inherited properties shared with others of your bloodline
6.drawing of fluid or inflammation away from a diseased part of the body
7.drawing off water from its main channel as for irrigation