Emily Dickinson Lexicon

AD'IT, n. [L. aditus, from adeo, aditum, to approach, ad and eo, to go.]

An entrance or passage; a term in mining, used to denote the opening by which a mine is entered, or by which water and ores are carried away. It is usually made in the side of a hill. The word is sometimes used for air-shaft, but not with strict propriety. – Encyc.