accent vs grave accent

accent and grave accent both are nouns.

Word	Noun	Adjective	Verb	Adverb
accent	Yes	No	Yes	No
grave accent	Yes	No	No	No

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

accent: a diacritical mark used to indicate stress or placed above a vowel to indicate a special pronunciation
grave accent: a mark (`) placed above a vowel to indicate pronunciation

Other hyponyms of accent include stress mark, acute, acute accent, ague, grave, double acute accent, Hungarumlaut.

accent (noun)	grave accent (noun)
the relative prominence of a syllable or musical note (especially with regard to stress or pitch)	a mark (`) placed above a vowel to indicate pronunciation
distinctive manner of oral expression
a diacritical mark used to indicate stress or placed above a vowel to indicate a special pronunciation
the usage or vocabulary that is characteristic of a specific group of people
special importance or significance

accent (verb)	grave accent (verb)
put stress on; utter with an accent
to stress, single out as important