1. the source from which something derives (i.e. comes or issues);
"he prefers shoes of Italian derivation"
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'; `undo' from `do'
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