IPA: //ˈfaɪərfaɪt//
KK: /ˈfaɪərˌfaɪt/
A situation where two or more groups shoot at each other, usually in a military context.
The soldiers were involved in a fierce firefight with the enemy forces.
Firefight is formed from "fire" (from Old English "fyr", meaning combustion or flame) and "fight" (from Old English "feohtan", meaning to struggle or battle). The word describes the act of battling against a fire, typically in the context of firefighting efforts.
Think of 'fire' as the flame that needs to be battled ('fight') — that's why firefight means to struggle against a fire.