Origin of boatswainMiddle English boteswayne from Old English batswegen from bat, boat + an unverified form swegen, servant from or akin to Old Norse sveinn: see swain
also bo's'n or bos'n or bo·sun
Origin of boatswainMiddle English botswein bot boat ; see boat . swein mate ; see swain .
Usage Note: The word boatswain is pronounced as a single word with two syllables (bō′sən). People with sea legs have a long tradition of spelling the word as bosun, bo's'n, and bos'n to reflect the salty pronunciation. This of course has not prevented landlubbers from using the incorrect two-word pronunciation (bōt′swān′). Many other nautical words have similarly tricky shipboard pronunciations, including bowline, pronounced (bō′lĭn); forecastle, pronounced (fōk′səl) and sometimes spelled fo'c's'le; gunwale, pronounced (gŭn′əl) and also sometimes spelled gunnel; mainsail, pronounced (mān′səl); and topgallant, pronounced (tə-găl′ənt). With the exception of gunwale, however, all of these terms can be correctly pronounced as if they were two words.