Page within a page, it's entangled? (5)
I believe the answer is:
inset
'page within a page' is the definition.
(I've seen this before)
'it's entangled?' is the wordplay.
I cannot quite understand how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
The remaining letters 'inse' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for inset that I've seen before include "Additional insert" , "Gore" , "Tines (anag.)" , "Small picture within borders of another" , "Picture placed within another" .)