Pernoctation, a not-so-common word, means “the act or state of passing the whole night; a remaining all night”.
There isn’t much to say about this word, really. It’s simple and straightforward. Per (meaning “through”) + noct (meaning “night”, as in nocturnal) + ation (a common suffix meaning “action or process”). There you have it: pernoctation, the action of staying through the whole night.
I haven’t found any examples of this word used in a sentence, though. In fact, my spell checker doesn’t even recognize it as a word! But I’m going to bring it back into common usage. I know plenty of students at college that could make good use of it. (They’re always jealous of me and my daily nine hours of sleep. ;) )