bosun vs bos'n

bosun and bos'n both are nouns.

Word	Noun	Adjective	Verb	Adverb
bosun	Yes	No	No	No
bos'n	Yes	No	No	No

As nouns, bosun and bos'n are synonyms defined as:

bosun and bos'n: a petty officer on a merchant ship who controls the work of other seamen

Other synonyms of bosun include bo's'n, bo'sun, boatswain.

bosun (noun)	bos'n (noun)
a petty officer on a merchant ship who controls the work of other seamen	a petty officer on a merchant ship who controls the work of other seamen