check in phrasal verb ( see also ↑ check )
1 . if you check in or are checked in at a hotel or airport, you go to the desk and report that you have arrived:
Check in two hours before the flight.
check in at
He checked in at the Europa Hotel.
check somebody ↔ in
Airline employees were checking in passengers.
⇨ ↑ check-in
2 . check something ↔ in to leave your bags at an official place so they can be put on a plane or a train, or to take someone’s bags in order to do this:
I said goodbye and went to check in my suitcases.
3 . American English to call someone to tell them that you are safe or where you are:
He just called to check in and tell them how he was doing.