reduction

noun

re·​duc·​tion ri-ˈdək-shən 

plural reductions

1

: the act or process of reducing : the state of being reduced

2

a

: something made by reducing

b

: the amount by which something is reduced

3

[Spanish reducción, from Latin reduction-, reductio] : a South American Indigenous settlement directed by Jesuit missionaries

4

: meiosis sense 2

specifically : production of the gametic chromosome number in the first meiotic division

reductional

ri-ˈdək-sh(ə-)nəl 

adjective

Synonyms of reduction

• deduction
• discount

Examples of reduction in a Sentence

a drastic reduction in size

Many voters want to see some reduction of the deficit.

There is a 20 percent reduction on selected items during this sale.

Recent Examples on the Web

That 1 % to 5% would be enough to demonstrate a statistically significant reduction in contrail formation on an airspace-scale, said Paul Hodgson, Google's technical lead for Operation Blue Skies. — ABC News, 18 Aug. 2026

Along with surveillance and global risk-reduction initiatives, Washington successfully deterred such attacks with the threat of significant retaliation, including the use of nuclear weapons. — Elizabeth Sherwood-Randall, Foreign Affairs, 18 Aug. 2026

In July 2025, states participating in RGGI jointly announced a plan to expedite the reduction of carbon emissions by up to 90% over the next decade. — John Moritz, Hartford Courant, 18 Aug. 2026

Similarly, competition has led to price reductions for Stelara, a popular biologic medicine that treats chronic inflammatory conditions, said Stacie Dusetzina, a professor of health policy at Vanderbilt University School of Medicine. — Ali Swenson, Los Angeles Times, 18 Aug. 2026

Word History

Etymology

Middle English reduccion restoration, from Middle French reducion, from Late Latin & Latin; Late Latin reduction-, reductio reduction (in a syllogism), from Latin, restoration, from reducere

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing reduction

• oxidation-reduction
• reduction division
• reduction gear

Rhymes for reduction

• abduction
• adduction
• conduction
• construction
• deduction
• destruction
• eduction
• induction
• instruction
• obstruction
• production
• seduction

Kids Definition

reduction

noun

re·​duc·​tion ri-ˈdək-shən 

1

: the act or process of reducing : the state of being reduced

2

a

: something made by reducing

b

: the amount by which something is reduced in price

3

: meiosis

especially : halving of the chromosome number in the reduction division

reductive

-ˈdək-tiv

adjective

Medical Definition

reduction

noun

re·​duc·​tion ri-ˈdək-shən 

1

: the replacement or realignment of a body part in normal position or restoration of a bodily condition to normal

2

: the process of reducing by chemical or electrochemical means

3

: the psychological diminishment of emotion or needs through activity or adjustment

4

: meiosis

specifically : production of the gametic chromosome number in the first meiotic division