dame vs grande dame

dame and grande dame both are nouns.

Word	Noun	Adjective	Verb	Adverb
dame	Yes	No	No	No
grande dame	Yes	No	No	No

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

dame: a woman of refinement
grande dame: a middle-aged or elderly woman who is stylish and highly respected

dame (noun)	grande dame (noun)
informal terms for a (young) woman	a middle-aged or elderly woman who is stylish and highly respected
a woman of refinement