1
: one who acts or transacts business for another: such as
a
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 factor in the decision
(2)
: a substance that functions in or promotes the function of a particular physiological process or bodily system
a clotting factor that facilitates blood coagulation
b
: a good or service (such as land, labor, or capital) 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 (see product sense 1)
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 factor of 10
factored; factoring
ˈfak-t(ə-)riŋ 
: to work as a factor
1
: to resolve into factors
2
a
: to include or admit as a factor
—used with in or into
factor inflation into our calculations
b
: to exclude as a factor
—used with out
Did you know?
In Latin factor means simply "doer". So in English a factor is an "actor" or element or ingredient in some situation or quantity. Charm can be a factor in someone's success, and lack of exercise can be a factor in producing a poor physique. In math we use factor to mean a number that can be multiplied or divided to produce a given number (for example, 5 and 8 are factors of 40). And in biology a gene may be called a factor, since genes are ingredients in the total organism.
Examples of factor in a Sentence
Noun
There were several factors contributing to their recent decline.
Poor planning was a major factor in the company's failure.
6, 4, 3, and 2 are factors of 12.
Verb
you should factor in inflation in making investment decisions
Recent Examples on the Web
Jim Augerinos, Travel + Leisure, 31 Oct. 2025
Women typically spend the middle 60% of their lives in relatively ill-health, due to hormonal changes, diagnostic delays, and other factors, and the last 30% of their lives in relatively good health.
—Alexei Oreskovic, Fortune, 30 Oct. 2025
Chris Vannini, New York Times, 30 Oct. 2025
Retailers are also feeling the impact; some may quietly factor higher shipping expenses into their prices.
—Elizabeth Fogarty, Better Homes & Gardens, 28 Oct. 2025
See All Example Sentences for factor
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Noun
This is where luxury, experience, and wow-factor meet.
—Jim Augerinos, Travel + Leisure, 31 Oct. 2025
Women typically spend the middle 60% of their lives in relatively ill-health, due to hormonal changes, diagnostic delays, and other factors, and the last 30% of their lives in relatively good health.
—Alexei Oreskovic, Fortune, 30 Oct. 2025
Verb
When factoring in the access to talent, the fan support, the unique tie LSU has to its local talent and the three national championships since 2003, the job offers almost everything a coach would want.
—Chris Vannini, New York Times, 30 Oct. 2025
Retailers are also feeling the impact; some may quietly factor higher shipping expenses into their prices.
—Elizabeth Fogarty, Better Homes & Gardens, 28 Oct. 2025
See All Example Sentences for factor
Cite this Entry
“Factor.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/factor. Accessed 31 Oct. 2025.
Copy CitationKids Definition
factor
1 of 2 noun
fac·tor
ˈfak-tər
1
: one that buys or sells property for another : agent
2
: something that contributes to the production of a result
price wasn't a factor in our decision
3
: gene
4
: any of the numbers or symbols in mathematics that when multiplied together form a product
especially
: a number that divides another number without leaving a remainder
the factors of 6 are 1, 2, 3, and 6
factor
2 of 2 verb
factored; factoring
-t(ə-)riŋ
1
: to find the mathematical factors of and especially the prime mathematical factors
2
: to act as a factor
attendance will factor into your grade
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