trousers vs. slacks

noun

(used with a plural verb)
  1. Sometimes Also called pants. a usually loose-fitting outer garment for the lower part of the body, having individual leg portions that reach typically to the ankle but sometimes to any of various other points from the upper leg down. Compare Bermuda shorts, breeches, knickers ( def 1 ), short ( def 29a ), slacks.


noun

(used with a plural verb)
  1. men's or women's trousers for informal wear.