Occupancy means the state of occupying or living in a building or space. When a hotel has high occupancy, most of its rooms are filled with guests. When a new apartment building reaches full occupancy, every unit has tenants living in it.

The word comes from occupy, which means to take up or fill a space. You'll often see occupancy mentioned in safety rules: a sign that says “Maximum occupancy: 100 people” means that's the most people who can safely fit in that space at once, based on fire codes and building regulations.

Businesses track occupancy carefully. A movie theater measures occupancy to know how many tickets to sell. A parking garage monitors occupancy to tell drivers whether spaces are available. Schools calculate classroom occupancy when deciding how many students can learn comfortably in each room.

The word can also refer to the act of taking possession of a space. When a family moves into a new house, their occupancy begins on that date. When a group stages an occupancy of a building to make a political statement, they are deliberately filling and controlling that space.