register vs enrol

register is a noun but enrol is not a noun.

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

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

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

Other hyponyms of register include file, register, patent, enroll, enter, inscribe, raise, recruit, list, book.

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

Other hypernyms of register include enroll, enter, inscribe, raise, recruit.

register (noun)	enrol (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

register (verb)	enrol (verb)
enter into someone's consciousness	register formally as a participant or member
indicate a certain reading; of gauges and instruments
record in a public office or in a court of law
send by registered mail
manipulate the registers of an organ
be aware of
show in one's face
record in writing; enter into a book of names or events or transactions
enroll to vote
have one's name listed as a candidate for several parties