reduce

American  

[ri-doos, -dyoos] / rɪˈdus, -ˈdyus /

verb (used with object)

reduces, present (3rd person singular) reduced, past participle, past reducing present participle

1. to bring down to a smaller extent, size, amount, number, etc..

   to reduce one's weight by 10 pounds.

   Synonyms:

   abate, attenuate, lessen, retrench, contract, curtail, abridge, shorten, decrease, diminish

   Antonyms:

   increase

2. to lower in degree, intensity, etc..

   to reduce the speed of a car.

   Synonyms:

   abate, attenuate, lessen

3. to bring down to a lower rank, dignity, etc..

   a sergeant reduced to a corporal

   Synonyms:

   humble, demote, degrade

   Antonyms:

   exalt, elevate

4. to treat analytically, as a complex idea.

5. to lower in price.

6. to bring to a certain state, condition, arrangement, etc..

   to reduce glass to powder.

7. to bring under control or authority.

   Synonyms:

   overpower, overcome, vanquish, subject, conquer, subjugate, subdue

8. Cooking. to evaporate water from (a sauce, soup, or other liquid), usually by boiling.

9. Photography. to lessen the density of (an exposed negative).

10. to adjust or correct by making allowances, as an astronomical observation.

11. Mathematics. to change the denomination or form, but not the value, of (a fraction, polynomial, etc.).

12. Chemistry.

    1. to add electrons to.

    2. to deoxidize.

    3. to add hydrogen to.

    4. to change (a compound) so that the valence of the positive element is lower.

13. Chemistry, Metallurgy. to bring into the metallic state by separating from nonmetallic constituents.

14. to thin or dilute.

    to reduce paint with oil or turpentine.

15. to lower the alcoholic concentration of (spirits) by diluting with water.

16. Surgery. to restore to the normal place, relation, or condition, as a fractured bone.

17. Phonetics. to modify the quality of (a speech sound) to one of lesser distinctiveness, especially to pronounce (an unstressed vowel) as (ə) or another centralized vowel, as in the unstressed syllables of medicinal.

---

verb (used without object)

reduces, present (3rd person singular) reduced, past participle, past reducing present participle

1. to become reduced.

2. to become lessened, especially in weight.

3. to be turned into or made to equal something.

   All our difficulties reduce to financial problems.

4. Cell Biology. to undergo meiosis.

reduce British  

/ rɪˈdjuːs /

verb

1. (also intr) to make or become smaller in size, number, extent, degree, intensity, etc

2. to bring into a certain state, condition, etc

   to reduce a forest to ashes

   to reduce someone to despair

3. (also intr) to make or become slimmer; lose or cause to lose excess weight

4. to impoverish (esp in the phrase in reduced circumstances )

5. to bring into a state of submission to one's authority; subjugate

   the whole country was reduced after three months

6. to bring down the price of (a commodity)

   the shirt was reduced in the sale

7. to lower the rank or status of; demote

   he was reduced from corporal to private

   reduced to the ranks

8. to set out systematically as an aid to understanding; simplify

   his theories have been reduced in a popular treatise

9. maths to modify or simplify the form of (an expression or equation), esp by substitution of one term by another

10. cookery to make (a sauce, stock, etc) more concentrated by boiling away some of the water in it

11. to thin out (paint) by adding oil, turpentine, etc; dilute

12. (also intr) chem

    1. to undergo or cause to undergo a chemical reaction with hydrogen or formation of a hydride

    2. to lose or cause to lose oxygen atoms

    3. to undergo or cause to undergo an increase in the number of electrons Compare oxidize

13. photog to lessen the density of (a negative or print) by converting some of the blackened silver in the emulsion to soluble silver compounds by an oxidation process using a photographic reducer

14. surgery to manipulate or reposition (a broken or displaced bone, organ, or part) back to its normal site

15. (also intr) biology to undergo or cause to undergo meiosis

---

Other Word Forms

Derived Forms

• nonreducing
  adjective
• antireducing
  adjective
• reducible
  adjective
• overreduce
  verb
• reducibility
  noun
• reducibly
  adverb

Conjugated Forms

Present

• has reduced
  perfect 3rd person singular
• have reduced
  perfect
• are reducing
  progressive
• has been reducing
  perfect progressive 3rd person singular
• have been reducing
  perfect progressive
• reducing
  participle
• am reducing
  progressive 1st person singular
• reduces
  singular 3rd person
• is reducing
  progressive 3rd person singular

Past

• had reduced
  perfect
• had been reducing
  perfect progressive
• were reducing
  progressive plural
• reduced
  simple
• reduced
  participle
• was reducing
  progressive singular

Future

• will reduce
  simple
• will have reduced
  perfect
• will be reducing
  progressive
• will have been reducing
  perfect progressive

Etymology

Origin of reduce

First recorded in 1325–75; Middle English reducen “to lead back,” from Latin redūcere “to lead back, bring back,” equivalent to re- re- + dūcere “to lead”

Explanation

You reduce something when you lessen its volume, size, or degree. That's why we say when someone goes on a diet, it's because they want to reduce; it's a polite way of suggesting they need to drop pounds and become a smaller size. The word reduce first appeared in Old French during the 14th Century, when it meant "bring back." From the Latin re, which meant "back," coupled with ducere, meaning "bring or lead" — we ended up with reduce. The current meaning, "to lessen," appeared in the late 1700's, drawn from the word's military use, "reduce to ranks," which meant break into smaller units. Cooks use the word reduce when they reduce a liquid, boiling it down until it has less volume and is thicker.

Example Sentences

He also announced an overhaul of the state bureaucracy that would reduce the number of ministries and trim the the state workforce, a plan that requires parliamentary approval in July.

From Barron's • Jun. 12, 2026

Weeks had to fend off calls by shareholders to lay off employees, or reduce investment in R&D and factories.

From The Wall Street Journal • Jun. 12, 2026

If successful in people, the approach could reduce the need for knee and hip replacement surgeries.

From Science Daily • Jun. 12, 2026

Health Secretary James Murray said the plan would "help more people build exercise into their everyday lives, improving public health and supporting our ambition to reduce pressure on the NHS".

From BBC • Jun. 12, 2026

Dismissing the impact of disease, in her view, is simply a way to reduce the original population of the Americas.

From "1491" by Charles C. Mann

Related Words

• curtail
• cut
• cut down
• diminish
• dwindle
• knock off
• lessen
• lower
• pare
• scale down
• shorten
• slash
• trim
• weaken