If you reduce something it means you make it smaller.
The noun of reduce is reduction.
Allthwaite’s Ltd have reduced their staff by 10% to cut costs.
In Business English, the word reduce is often used in relation to prices:
Krazy Karpets, the No.1 place for carpets, have got some MASSIVE reductions this summer. 75% off – we  can’t be beaten on price!
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