lighter vs firelighter

lighter and firelighter both are nouns.

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

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

lighter: a substance used to ignite or kindle a fire
firelighter: (a piece of) a substance that burns easily and can be used to start a coal or coke fire

Other hyponyms of lighter include kindling, punk, spunk, tinder, touchwood, punk.

lighter (noun)	firelighter (noun)
a device for lighting or igniting fuel or charges or fires	(a piece of) a substance that burns easily and can be used to start a coal or coke fire
a flatbottom boat for carrying heavy loads (especially on canals)
a substance used to ignite or kindle a fire

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