noun, noun or participle which takes 'suru', intransitive verb
check-in
Refers to the process of registering arrival at a hotel, airport, or event. Used as both a noun and a suru-verb.
ホテルでチェックインを済ませた。
I completed check-in at the hotel.
空港でチェックインするのに時間がかかった。
It took time to check in at the airport.
チェックアウト means 'check-out', the process of leaving and settling a bill, while チェックイン is for arrival registration.
Borrowed from English 'check-in'.