This meaning refers to a tunnel driven from the surface into a mine, usually with little or no downward slope.
The miners entered through the eastern adit.
The old adit had collapsed near the entrance.
This technical use emphasizes the practical function of an adit in removing water, moving people and ore, or supplying ventilation.
The lower adit drained water from the workings.
Fresh air entered the mine through a separate adit.
This broader engineering meaning refers to a side tunnel providing access to an underground work area, not necessarily a mine.
Engineers excavated an adit to inspect the dam foundations.
The project used a temporary adit for construction access.
