Noun
a type of ledger in which visitors to a particular establishment, such as a bed and breakfast or a museum, may leave comments about the establishment.
(Internet) a feature of a website performing a similar function to a physical guest book
Source: en.wiktionary.orgWe still lend our old house out to relatives. They keep a guest book for my fans to sign. Loretta Lynn
It is difficult sharing and capturing so many years of memories and the people behind the words-and even though that guest book can speak volumes, in between, the pages remain so silent. Eugenie Anderson