Seal is broken revealing passages (6)
I believe the answer is:
aisles
'passages' is the definition.
(aisle is a kind of passage)
'seal is broken' is the wordplay.
'broken' indicates anagramming the letters.
'seal'+'is'='sealis'
'sealis' anagrammed gives 'AISLES'.
'revealing' is the link.
(Other definitions for aisles that I've seen before include "Lassie (anag.)" , "Paths in church for lassie" , "Supermarket sections" , "Church corridors for lassie" , "Passages between rows of seats" .)