highlighter vs marker

highlighter and marker both are nouns.

Word	Noun	Adjective	Verb	Adverb
highlighter	Yes	No	No	No
marker	Yes	No	No	No

As nouns, marker is a hypernym of highlighter; that is, marker is a word with a broader meaning than highlighter:

highlighter (noun)	marker (noun)
a fluorescent marker used to mark important passages in a text	some conspicuous object used to distinguish or mark something
a cosmetic used to highlight the eyes or cheekbones	a writing implement for making a mark
	a distinguishing symbol