Cranny, fissure (7)
I believe the answer is:
crevice
I believe this is a double definition.
'cranny' is the first definition.
(I know that cranny can be written as crevice)
'fissure' is the second definition.
(I know that fissure can be written as crevice)
(Other definitions for crevice that I've seen before include "Crack or fissure." , "Split" , "Narrow crack" , "Narrow rock fissure" , "Opening" .)