Concerning number of roach trails identified at intervals (5)
I believe the answer is:
octal
'roach trails identified at intervals' is the definition.
I can't judge whether this definition defines the answer.
'concerning number' is the wordplay.
'concerning' becomes 'octa' (I am not sure about this - if you are sure you should believe this answer much more).
'number' becomes 'L' (L is an example).
'octa'+'l'='OCTAL'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for octal that I've seen before include "Using 8 as base (maths)" , "Working in base 8" , "with unusual base" , "Relating to the number 8" , "(Of numbers) in base 8" .)
