flatboat vs lighter

flatboat and lighter both are nouns.

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

As nouns, flatboat and lighter are synonyms defined as:

flatboat and lighter: a flatbottom boat for carrying heavy loads (especially on canals)

Other synonyms of flatboat include barge, hoy.

flatboat (noun)	lighter (noun)
a flatbottom boat for carrying heavy loads (especially on canals)	a device for lighting or igniting fuel or charges or fires
	a flatbottom boat for carrying heavy loads (especially on canals)
	a substance used to ignite or kindle a fire

flatboat (verb)	lighter (verb)
	transport in a flatbottom boat