1. Announce one's arrival, e.g. at hotels or airports
   "We checked in at the hotel reception desk";
   - sign in
    
2. Contact or visit another person in order to keep them informed of one's situation or see how they are
   "My son checks in regularly with me when he's travelling"

1. The act of reporting your presence, as at an airport or a hotel
   "The hotel's automated check-in system sped up the process"

Derived forms: check-ins, checking in, checks in, checked in

Type of: arrival, report

Antonym: check out

Encyclopedia: Check in