collection vs pickup

collection and pickup both are nouns.

Word	Noun	Adjective	Verb	Adverb
collection	Yes	No	No	No
pickup	Yes	No	No	No

As nouns, pickup is a hyponym of collection; that is, pickup is a word with a more specific, narrower meaning than collection:

collection (noun)	pickup (noun)
the act of gathering something together	the act or process of picking up or collecting from various places
a publication containing a variety of works	the act of taking aboard passengers or freight
request for a sum of money	a light truck with an open body and low sides and a tailboard
several things grouped together or considered as a whole	an electro-acoustic transducer that is the part of the arm of a record player that holds the needle and that is removable
	mechanical device consisting of a light balanced arm that carries the cartridge
	anything with restorative powers
	the attribute of being capable of rapid acceleration
	a warrant to take someone into custody
	a casual acquaintance; often made in hope of sexual relationships