Has it a regular route around the interior? (5)
I believe the answer is:
liner
'has it a' is the definition.
I can't tell whether this definition defines the answer.
'regular route around the interior?' is the wordplay.
'regular route' becomes 'line' (line is a kind of route. I am not sure about the 'regular' bit.**).
'around' becomes 'circa' (I've seen this before).
'the interior?' means to look at the middle letters (I've seen 'interior' mean this).
The centre of 'circa' is 'r'.
'line'+'r'='LINER'
Can you help me to learn more?
(Other definitions for liner that I've seen before include "may be demonstrated by make-up artist" , "QE2, perhaps" , "Passenger transport" , "Large ship or removable layer of material" , "Cosmetic; fine paintbrush" .)