[ fak-ter ]
See synonyms for factor on Thesaurus.com
  1. one of the elements contributing to a particular result or situation: Poverty is only one of the factors in crime.

  2. Mathematics. one of two or more numbers, algebraic expressions, or the like, that when multiplied together produce a given product; a divisor: 6 and 3 are factors of 18.

  1. Biochemistry. any of certain substances necessary to a biochemical or physiological process, especially those whose exact nature and function are unknown.

  2. a business organization that lends money on accounts receivable or buys and collects accounts receivable.

  3. a person who acts or transacts business for another; an agent.

  4. an agent entrusted with the possession of goods to be sold in the agent's name; a merchant earning a commission by selling goods belonging to others.

  5. a person or business organization that provides money for another's new business venture; one who finances another's business.

  6. Scot. the steward or bailiff of an estate.

verb (used with object)
  1. Mathematics. to express (a mathematical quantity) as a product of two or more quantities of like kind, as 30 = 2·3·5, or x2y2 = (x + y) (x − y).: Compare expand (def. 4a).

  2. to act as a factor for.

verb (used without object)
  1. to act as a factor.

Verb Phrases
  1. factor in / into to include as an essential element, especially in forecasting or planning: You must factor insurance payments into the cost of maintaining a car.

Origin of factor

First recorded in 1400–50; late Middle English facto(u)r, from Latin factor “maker, perpetrator,” equivalent to fac(ere) “to make, do” + -tor agent noun suffix; see -tor

Other words from factor

  • fac·tor·a·ble, adjective
  • fac·tor·a·bil·i·ty, noun
  • fac·tor·ship, noun
  • sub·fac·tor, noun
  • un·der·fac·tor, noun
  • un·fac·tor·a·ble, adjective
  • un·fac·tored, adjective

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use factor in a sentence

  • We can make no statements about the Mendelian inheritance of such a trait until it is factored into its units.

    The Social Direction of Evolution | William E. Kellicott

British Dictionary definitions for factor


/ (ˈfæktə) /

  1. an element or cause that contributes to a result

  2. maths

    • one of two or more integers or polynomials whose product is a given integer or polynomial: 2 and 3 are factors of 6

    • an integer or polynomial that can be exactly divided into another integer or polynomial: 1, 2, 3, and 6 are all factors of 6

  1. (foll by identifying numeral) med any of several substances that participate in the clotting of blood: factor VIII

  2. a person who acts on another's behalf, esp one who transacts business for another

  3. commerce a business that makes loans in return for or on security of trade debts

  4. former name for a gene

  5. commercial law a person to whom goods are consigned for sale and who is paid a factorage

  6. (in Scotland) the manager of an estate

  1. (intr) to engage in the business of a factor

Origin of factor

C15: from Latin: one who acts, from facere to do

usage For factor

Factor (sense 1) should only be used to refer to something which contributes to a result. It should not be used to refer to a part of something such as a plan or arrangement; instead a word such as component or element should be used

Derived forms of factor

  • factorable, adjective
  • factorability, noun
  • factorship, noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for factor


[ făktər ]

  1. One of two or more numbers or expressions that are multiplied to obtain a given product. For example, 2 and 3 are factors of 6, and a + b and a - b are factors of a2 - b2.

  2. A substance found in the body, such as a protein, that is essential to a biological process. For example, growth factors are needed for proper cell growth and development.

  1. To find the factors of a number or expression. For example, the number 12 can be factored into 2 and 6, or 3 and 4, or 1 and 12.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.