Meaning of “register” - Learner’s Dictionary

register

verb uk us /ˈredʒɪstər/
ON A LIST [ I, T ]

B1 to put information about someone or something, especially a name, on an official list:

Is he registered with the authorities to sell alcohol?
Students need to register for the course by the end of April.
a registered nurse
SHOW A FEELING [ T ]

to show an opinion or feeling:

People gathered to register their opposition to the plans.
SHOW AMOUNT [ I, T ]

to show an amount on an instrument that measures something:

The earthquake registered 7.3 on the Richter scale.

(Definition of “register verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)