enter vs register

enter is not a noun while register is a noun.

Word	Noun	Adjective	Verb	Adverb
enter	No	No	Yes	No
register	Yes	No	Yes	No

As verbs, register is a hyponym of enter; that is, register is a word with a more specific, narrower meaning than enter:

enter: make a record of; set down in permanent form
register: record in writing; enter into a book of names or events or transactions

As verbs, register is a hypernym of enter; that is, register is a word with a broader meaning than enter:

enter: register formally as a participant or member
register: record in writing; enter into a book of names or events or transactions

As verbs, register is a hyponym of enter; that is, register is a word with a more specific, narrower meaning than enter:

Other hyponyms of enter include draft, enlist, muster in, unionise, unionize, matriculate.

enter (noun)	register (noun)
	a regulator (as a sliding plate) for regulating the flow of air into a furnace or other heating device
	an air passage (usually in the floor or a wall of a room) for admitting or excluding heated air from the room
	a cashbox with an adding machine to register transactions; used in shops to add up the bill
	(computer science) memory device that is the part of computer memory that has a specific address and that is used to hold information of a specific kind
	(music) the timbre that is characteristic of a certain range and manner of production of the human voice or of different pipe organ stops or of different musical instruments
	an official written record of names or events or transactions
	a book in which names and transactions are listed

enter (verb)	register (verb)
set out on (an enterprise or subject of study)	enter into someone's consciousness
make a record of; set down in permanent form	indicate a certain reading; of gauges and instruments
become a participant; be involved in	record in a public office or in a court of law
put or introduce into something	send by registered mail
come on stage	manipulate the registers of an organ
to come or go into	be aware of
take on duties or office	show in one's face
register formally as a participant or member	record in writing; enter into a book of names or events or transactions
be or play a part of or in	enroll to vote
	have one's name listed as a candidate for several parties