Also found in: Thesaurus, Encyclopedia, Wikipedia.
A door made of fire-resistant material that can be closed to prevent the spread of fire.
1. (Building) a door made of noncombustible material, the purpose of which is to prevent a fire from spreading within a building
2. (Building) a similar door, leading to the outside of a building, that can be easily opened from inside; emergency exit
a fireproof or fire-resistant door in a building.