noun Someone (especially male) who is skilled in the work of fighting fire.
noun A person (originally a man) who keeps the fire going underneath a steam boiler (originally, shoveling coal by hand), particularly on a railroad locomotive or steamship.
The fireman's job was about to get very interesting; they had just run out of coal!
noun An assistant on any locomotive, whether steam-powered or not.
noun A relief pitcher (reflecting the figurative analogy of rescuing the situation).