Reserve part of NT's web address (8)
I believe the answer is:
bookmark
'web address' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'reserve part of nt's' is the wordplay.
'reserve' becomes 'book' (to book something is to reserve it).
'part of nt' becomes 'Mark' (book of the New Testament).
'book'+'mark'='BOOKMARK'
Can you help me to learn more?
(Other definitions for bookmark that I've seen before include "It helps to know one's place" , "note address" , "Strip inserted between pages as indicator" , "Reader's place keeper" , "Link" .)