Merriam-Webster Collegiate Dictionary - derivation

 noun  Date: 15th century  1.  a.  (1) the formation of a word from another word or base (as by the addition of a usually noninflectional affix)  (2) an act of ascertaining or stating the ~ of a word  (3) etymology 1  b. the relation of a word to its base  2.  a. source, origin  b. descent, origination  3. something derived ; derivative  4. an act or process of deriving  5. a sequence of statements (as in logic or mathematics) showing that a result is a necessary consequence of previously accepted statements  • ~al adjective