booster vs relay link

booster and relay link both are nouns.

Word	Noun	Adjective	Verb	Adverb
booster	Yes	No	No	No
relay link	Yes	No	No	No

As nouns, booster and relay link are synonyms defined as:

booster and relay link: an amplifier for restoring the strength of a transmitted signal

Other synonyms of booster include booster amplifier, booster station, relay station, relay transmitter.

booster (noun)	relay link (noun)
an additional dose that makes sure the first dose was effective	an amplifier for restoring the strength of a transmitted signal
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.