Longman Dictionary of Contemporary English
Wiktionary
n. A fireproof door designed to stop fires spreading through buildings.
WordNet
n. a fire-resistant door that can be closed to stop the spread of a fire
Wikipedia
A fire door is a door with a fire-resistance rating (sometimes referred to as a fire protection rating for closures) used as part of a passive fire protection system to reduce the spread of fire and smoke between separate compartments of a structure and to enable safe egress from a building or structure or ship. In North American building codes, it, along with fire dampers, is often referred to as a closure, which can be derated compared against the fire separation that contains it, provided that this barrier is not a firewall or an occupancy separation. In Europe national standards for fire doors have been harmonised with the introduction of the new standard EN 16034, which refers to fire doors as fire-resisting door sets. Starting September 2016, a common CE marking procedure will be available abolishing trade barriers within the European Union for these types of products. In the UK, it is Part B of the Building Regulations that sets out the minimum requirements for the fire protection that must be implemented in all dwellings this includes the use of fire doors. All fire door must be installed with the appropriately fire resistant fittings, such as the frame and door hardware, for it to fully comply with any fire regulations.
Usage examples of "fire door".
At the top of some wooden steps was a metal fire door that could only be opened from the inside.
Then he jerked the fire door open but did not step into the stairwell.
There were still noises coming from the other side of the fire door.
In less than two minutes, the Knight of the Word had disposed of all five assailants and disappeared through the fire door.