'ardoise' originates from French, specifically the word 'ardoise', where the French term denotes a slate or flat stone used for roofing and writing.

'ardoise' passed into English from French (Old French/Modern French 'ardoise'), ultimately tracing back to Late Latin 'ardesia' (also attested in Italian as 'ardesia' and Occitan/Provençal forms), from a pre-Latin substrate in western Europe.

Initially it referred to the material (a flat stone or slate) used for roofing or as a writing tablet; over time the English use retained that sense but remained relatively rare and specialized.