Emily Dickinson Lexicon

SLATE, n. [Fr. eclater, to split, Sw. slita; Ir. sglata, a tile. Class Ld.]

1. An argillaceous stone which readily splits into plates; argillite; argillaceous shist.
2. A piece of smooth argillaceous stone, used for covering buildings.
3. A piece of smooth stone of the above species, used for writing on.