to make something smaller in size, amount, price, or level
The store reduced the price of the jacket by 30 percent.
Turning off unused lights can reduce your electricity bill.
✦ From Latin ‘reducere’ meaning ‘to lead back’ → ‘to bring down’.
to change a fraction or mathematical expression to a simpler form without changing its value
She reduced the fraction 6⁄8 to 3⁄4.
You can reduce that equation by dividing both sides by 2.
to boil a liquid so that some water evaporates and it becomes thicker and stronger in flavour
Let the sauce simmer until it reduces by half.
The chef reduced the stock for an hour to make it rich and glossy.
in chemistry, to cause a substance to gain electrons, lowering its oxidation state
In the reaction, copper ions are reduced to solid copper.
Adding hydrogen can reduce certain metal oxides.
(dated) to force a place or group to surrender and come under control
The army reduced the fortress after a long siege.
The rebels were quickly reduced by the royal troops.
