Definition of au gratin in English:

au gratin

adjective

  • postpositive Sprinkled with breadcrumbs or grated cheese, or both, and browned.

    ‘lentils and mushrooms au gratin’
    • ‘These are the traditional components of potatoes au gratin.’
    • ‘I used to do a potato au gratin with mushrooms which I really like.’

Origin

French, literally ‘by grating’, from the verb gratter ‘to grate’.

Pronunciation