Meaning of “vest” - Learner’s Dictionary

vest

noun [ C ] us uk /vest/
UNDERWEAR UK US undershirt

a piece of underwear that you wear under a shirt

WORN OVER A SHIRT US UK waistcoat

a piece of clothing with buttons at the front and no sleeves, that you wear over a shirt

(Definition of “vest” from the Cambridge Learner’s Dictionary © Cambridge University Press)