Merriam-Webster Collegiate Dictionary - factor

 I. noun  Etymology: Middle English, from Middle French facteur, from Latin ~ doer, from facere  Date: 15th century  1. one who acts or transacts business for another: as  a. broker 1b  b. one that lends money to producers and dealers (as on the security of accounts receivable)  2.  a.  (1) one that actively contributes to the production of a result ; ingredient price wasn't a ~ in the decision  (2) a substance that functions in or promotes the function of a particular physiological process or bodily system  b. a good or service used in the process of production  3. gene  4.  a. any of the numbers or symbols in mathematics that when multiplied together form a product; also a number or symbol that divides another number or symbol  b. a quantity by which a given quantity is multiplied or divided in order to indicate a difference in measurement costs increased by a ~ of 10  • ~ship noun  II. verb  (~ed; ~ing)  Date: 1621  intransitive verb to work as a ~  transitive verb  1. to resolve into ~s  2.  a. to include or admit as a ~ — used with in or into ~ inflation into our calculations  b. to exclude as a ~ — used with out  • ~able adjective