k-in [noun] [C]A representative from the tour company will meet you at the check-in.A check-in desk/counter at an airport is a place where you report your arrival, leave your bags, and are given your seat number.(UK) A check-in hall is the area in an airport where people go to report their arrival and obtain information about flights.
CHEC
Meaning of CHEC in English
Cambridge English vocab. Кембриджский английский словарь. 2012