booster dose vs booster

booster dose and booster both are nouns.

Word	Noun	Adjective	Verb	Adverb
booster dose	Yes	No	No	No
booster	Yes	No	No	No

As nouns, booster dose and booster are synonyms defined as:

booster dose and booster: an additional dose that makes sure the first dose was effective

Other synonyms of booster dose include booster shot, recall dose.

booster dose (noun)	booster (noun)
an additional dose that makes sure the first dose was effective	an additional dose that makes sure the first dose was effective
	the first stage of a multistage rocket
	an amplifier for restoring the strength of a transmitted signal
	a thief who steals goods that are in a store
	someone who is an active supporter and advocate
	a person who backs a politician or a team etc.