What is "sign-in"

Usage examples of "sign-in".

And when he was printing his name on the sign-in sheet it matched the print of the joke on the gift card.

I put in a good word for you, but when the honchos came here from Dix and looked at all the blanks in the sign-in book, the shit hit the fan.

There was a sign-in book and a silver bowl containing jelly beans on the table.