Passageways (7)
'passageways' is the definition.
(tunnel is a kind of passageway)
This is all the clue.
(Another definition for tunnels that I've seen is " Underground passages".)
'passageways' is the definition.
(aisle is a kind of passageway)
This is the entire clue.
(Other definitions for aisles that I've seen before include "Passages between rows of seats" , "Paths in church for lassie" , "Total disorder" , "Lassie (anag.)" , "Supermarket sections" .)