check in

verb

1. To announce or record one's own arrival at a hotel, airport etc.

   “We got to the hotel last night and checked in at the front desk.”

2. To verify a person's information and record their arrival, such as at a hotel, airport, etc.

   “The clerk checked us in at the front desk.”

3. To contact another person in order to keep the other person informed of one's situation.

   “Kelly has to check in with her parole officer today.”

   “During the 2 minutes of music, students first PAUSE to check in with how they are feeling.”

4. To return (a book to a library, source code to a repository, etc.).
5. To visit in order to see how someone is doing.

   “I just wanted to check in after your accident. How are you recovering?”

   “The sequel checks in with the unmoored but largely lovable characters from the first movie as they face middle age.”

6. To enter solitary confinement at one's own request for protection from other prisoners.
7. To send somebody to solitary confinement; to make somebody be admitted to solitary confinement.
8. To integrate new revisions into the public or master version of a file in a version control system.
9. to tap on, to touch in, to tap in (to use a smartcard to start a public transport journey)

   “So how exactly does checking in work? When boarding the bus, tram, metro or train, hold the OV-chipkaart (or your debit card, smartphone, or wearable if using OVPay) in front of the screen of a post or gate. It will indicate with a green light and a beep that the anonymous OV-chipkaart has been read.”

   “You can check in and check out with a contactless debit card or credit card. Registering in advance is not necessary.”