Wiktionary
sleep in
vb. (context intransitive idiomatic English) To sleep late; to go on sleeping past one's customary or planned hour.
WordNet
sleep in
v. sleep later than usual or customary; "On Sundays, I sleep in" [syn: sleep late]
live in the house where one works; "our babysitter lives in, as it is too far to commute for her" [syn: live in] [ant: live out]
Usage examples of "sleep in".
From the shortness of the nights, they divided them into only two watches of from two hours to two and a half each, so that, even when constant watch duty was necessary, each man had one full night's sleep in three.