lighter vs flatboat

lighter and flatboat both are nouns.

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

As nouns, lighter and flatboat are synonyms defined as:

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

Other synonyms of lighter include barge, hoy.

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

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