flatboat vs scow

flatboat and scow both are nouns.

Word	Noun	Adjective	Verb	Adverb
flatboat	Yes	No	No	No
scow	Yes	No	No	No

As nouns, scow is a hyponym of flatboat; that is, scow is a word with a more specific, narrower meaning than flatboat:

Other hyponyms of flatboat include dredger, houseboat, pontoon, Norfolk wherry, wherry.

flatboat (noun)	scow (noun)
a flatbottom boat for carrying heavy loads (especially on canals)	a barge carrying bulk materials in an open hold
	any of various flat-bottomed boats with sloping ends