Adit and Crawl space

Adit noun - A nearly horizontal passage from the surface into a mine.

Crawl space and adit are semantically related In some cases you can use "Crawl space" instead a noun "Adit".

Crawl space noun - Low space beneath a floor of a building; gives workers access to wiring or plumbing.

Adit and crawl space are semantically related in covered passageway topic. You can use "Adit" instead a noun phrase "Crawl space".