Have now no beginning or end (3)
I believe the answer is:
own
'have' is the definition.
(to have something is to own it)
'now no beginning or end' is the wordplay.
'now' anagrams to 'OWN'.
However, I'm not sure how this is indicated.
Can you help me to learn more?
(Other definitions for own that I've seen before include "Control" , "Be in legal possession of (3)" , "Possess or confess" , "Possess - recognise - admit" , "Keep" .)