Adit

1. n. Admission; approach; access.
2. n. 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.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.