heater
UK: ˈhiːtə | US: ˈhiːtər
n. a device used to generate warmth or raise temperature
n. (slang) a firearm, especially a pistol
The word "heater" combines the Old English root "hǣtan" (to heat) with the agentive suffix "-er," which denotes a person or thing performing an action. The term emerged in Middle English as "hetere," referring to someone or something that heats. By the 19th century, it specifically denoted mechanical heating devices. The slang usage for "firearm" (early 20th century) metaphorically links the weapon's rapid firing to heat generation.
The electric heater kept the room warm during winter.
She turned on the car’s seat heater before driving.
In detective novels, "heater" often refers to a hidden gun.
The factory installed industrial heaters for the workers.
His old water heater broke down unexpectedly.