being unoccupied
"The hotel room was marked as available because there was a vacancy in that wing of the building."
An unoccupied position or job.
"The company is advertising several vacancies in their marketing department."
In plain English: A vacancy is an empty spot that needs to be filled, like an unfilled job opening or an available room for rent.
"The hotel had no vacancies left, so we couldn't book a room for tonight."
Vacancy comes from the Late Latin word vacantia, which originally meant something left empty or unoccupied. The term entered English as a doublet of "vacance," sharing the same root meaning but developing slightly different usage over time.