An underground, underwater, or mountain passage for transportation or utilities.

a passage dug under the ground, through a mountain, or under water; same as [[隧道|隧道|sui4 dao4]]

A metaphorical or imaginary passage connecting the past, present, and future.

carpal tunnel syndrome; median neuropathy at the wrist; a condition causing pain, numbness, or tingling in the hands due to pressure on the median nerve in the wrist