Fireman
Part of speech: noun
Definition: A person who is skilled in the work of fighting fire. A fireman that is of the male sex (see usage note). A man who keeps the fire going underneath a steam boiler (originally, shoveling coal by hand), particularly on a railroad locomotive. By extension of the above, an assistant on any locomotive, whether steam-powered or not. A relief pitcher.
Firefighter
Part of speech: noun
Definition: A person who puts out fires.