What does the word vacancies mean?

Answer 1

Vacancy means that there is an opening... so a sign on a building might mean there is an apartment for rent, at a hotel that they have rooms available, and in your mouth might mean there is a tooth missing.

Answer 2

A vacancy is an emptiness, something which is empty. A hotel room which nobody has rented is a vacancy. A political office which nobody is filling is a vacancy. These are the most common uses of the word. When a hotel puts up a sign saying "no vacancies" it means there are no rooms to rent. J.K. Rowling's novel The Casual Vacancy is about a vacant political office.