What does adit mean?
The definition of adit
Ad”it, n.
Etym: [L. aditus, fr. adire, , to go to; ad + ire to go.]

1 An entrance or passage. Specifically: The nearly horizontal opening by which a mine is entered, or by which water and ores are carried away; — called also drift and tunnel.
2 Admission; approach; access. [R.] Yourself and yours shall have Free adit. Tennyson.