Meaning of “blow” - Learner’s Dictionary

blow

noun [ C ] uk us /bləʊ/
DISAPPOINTMENT

a shock or disappointment:

Losing his job was a terrible blow to him.
HIT

a hard hit with a hand or heavy object:

He suffered serious blows to the head during the attack.
INSTRUMENT

the act of blowing something or blowing into an instrument or other object:

a blow on the whistle

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