1
                           general:: 
                            Phrase(s): check something in
1. to record that someone has returned something.  •  I asked the librarian to check the book in for me.  •  Did the librarian check in the book? 2. to take something to a place, return it, and make sure that its return has been recorded.  •  I checked the book in on time.  •  Did you really check in the book on time? 3. to examine a shipment or an order received and make certain that everything ordered was received.  •  I checked the order in and sent a report to the manager.  •  Tim checked in the order from the supplier to make sure that everything was there., Phrase(s): check in(to something) 
1. to sign oneself into a place to stay, such as a hotel, hospital, motel, etc.  •  She checked into a private hospital for some kind of treatment.  •  They checked into the first motel they came to on the highway. 2. Go to look into something., Phrase(s): check in (with someone) 
to go to someone and indicate that one has arrived some place.  •  Please check in with the desk clerk., Phrase(s): check in (at something) 
to go to a place to record one’s arrival.  •  When you get there, check in at the front office., Phrase(s): check in (on someone or something) 
Go to look in (on someone or something)., Phrase(s): check someone in 
to record the arrival of someone.  •  Ask the guard to check you in when you get there.  •  Tell the guard to check in the visitors as they arrive.
                        
                        
 
                        
                            McGrawhill's American Idioms And Phrasal Verbs
                        
                        
                    
                    
                        2
                           general:: 
                            1. Record one's arrival at a hotel, conference, or other function, as in I asked the hotel if we could check in early. [Early 1900s]  Also see  CHECK INTO, def. 2. 2. Die, as in With the plane rapidly losing fuel, the pilot was sure he'd check in. [Slang; early 1900s]  Also see  CHECK OUT.
                        
                        
 
                        
                            American Heritage Idioms