lineman vs linemen

lineman and linemen both are nouns.

Word	Noun	Adjective	Verb	Adverb
lineman	Yes	No	No	No
linemen	Yes	No	No	No

lineman (noun)	linemen (noun)
(American football) the position of a player on a football team who is stationed on the line of scrimmage	the football players who line up on the line of scrimmage
one of the players on the line of scrimmage
a person who installs or repairs electrical or telephone lines
the surveyor who marks positions with a range pole