Ends of branches regularly block the way (6)
I believe the answer is:
system
'the way' is the definition.
(I've seen this before)
'ends of branches regularly block' is the wordplay.
'ends of' indicates one should take the final letters (I've seen 'end of' mean this).
'block' becomes 'stem' (I've seen this before).
The final letters of 'branches regularly' are 'sy'.
'sy'+'stem'='SYSTEM'
(Other definitions for system that I've seen before include "Organised scheme" , "Organised whole made up of related parts" , "Network" , "Set of connected parts forming a working whole" , "Technique, method" .)