1. The act of reporting your presence (as at an airport or a hotel)

1. Announce one's arrival, e.g. at hotels or airports
   - sign in

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

Type of: arrival, report

Antonym: check out

Encyclopedia: Check in

• on-key
• on-license
• on-line database
• on-message
• on-off switch
• on-screen
• on-site
• on-street
• on-the-job
• on-the-scene
• onager
• Onagraceae
• onanism
• onanist
• once
• once again
• once and for all
• once in a blue moon
• once in a while
• once more
• once upon a time
• once-over
• onchocerciasis
• oncidium
• Oncidium papilio