Emily Dickinson Lexicon

FOG, n.¹ [In Sp. vaho is steam; vahar, to exhale. In Italian, sfogo is exhalation; sfogare, to exhale. In Scot. fog is moss. In Italian, affogare is to suffocate, Sp. ahocar. The sense probably is thick, or that which is exhaled.]

1. A dense watery vapor, exhaled from the earth, or from rivers and lakes, or generated in the atmosphere near the earth. It differs from mist, which is rain in very small drops.
2. A cloud of dust or smoke.