Definition of “reduce”

verb (mainly tr)

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. mathematics 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) chemistry 
    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. photography 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