The Collaborative International Dictionary
check in
check in \check` in"\ (ch[e^]k`[i^]n"), v. i. To register as a guest at a hotel, inn, motel. etc. Converse of check out.
Wiktionary
check in
vb. 1 To announce or record one's arrival at a hotel, airport etc. 2 To contact another person in order to keep the other person informed of one's situation. 3 (context transitive English) To return (a book to a library, source code to a repository, etc.).
WordNet
Wikipedia
Check In
Check In is the sole album by The Chalets, released in 2005.
Usage examples of "check in".
I expected to hear from her yesterday or the day before, just to check in with me before we switched over.
Detweiler left smiling, his check in Mklikluln's hand, even though the puppy had pooped on his shoe.
Silver said he'd preferred not to check in at the Kermandie system if he could avoid it.