check in

phr.v. to show your ticket or passport and get your room key or boarding pass.

phr.v. to register one's arrival at a hotel, airport, or clinic. Intransitive or transitive with 'at'.

“We need to check in at the hotel before we go out for dinner.”

“Passengers are advised to check in at least three hours before their international flight to allow sufficient time for security screenings.”

phr.v. to talk to someone to see if they are okay or to tell them where you are.

phr.v. to make contact with someone to provide an update or to monitor their status. Often used with the preposition 'with'.

“I'll check in with you tomorrow morning to see how the project is going.”

“The social worker promised to check in with the family twice a week to ensure the recovery process was proceeding as planned.”

phr.v. to save a new version of your work into a shared computer system.

phr.v. to commit or upload updated files to a central repository in a version control system.

“Don't forget to check in your code before you leave for the weekend.”

“The lead developer requested that all team members check in their final revisions by midnight to prepare for the morning deployment.”

Technical

phr.v. to tap your travel card on a reader when you start a journey.

phr.v. to validate a smartcard or ticket at the start of a journey on public transport. Common in European contexts.

“You must check in with your card at the yellow post before getting on the train.”

“Commuters who fail to check in at the station entrance may be liable for a fine even if they possess a valid monthly pass.”