grande dame

[ gran dam, deym; French grahnd dam ]
/ ˈgræn ˈdæm, ˈdeɪm; French grɑ̃d ˈdam /

noun, plural grandes dames [gran damz, deymz; French grahnd dam] /ˈgræn ˈdæmz, ˈdeɪmz; French grɑ̃d ˈdam/.

a usually elderly woman of dignified or aristocratic bearing.
a woman who is the doyenne of a specific field: a grande dame of the American theater.

Origin of grande dame

1735–45; < French: literally, great lady

British Dictionary definitions for grande dame

grande dame
/ French (ɡrɑ̃d dam) /

noun

a woman regarded as the most experienced, prominent, or venerable member of her profession, etc the grande dame of fashion