Combined to make notes about it (9)
I believe the answer is:
composite
'combined' is the definition.
(I've seen this before)
'notes about it' is the wordplay.
'notes' becomes 'compose' (I can't justify this - if you can you should believe this answer much more).
'about' means one lot of letters goes inside another.
'compose' going around 'it' is 'COMPOSITE'.
'to make' acts as a link.
Can you help me to learn more?
(Other definitions for composite that I've seen before include "An amalgam, made up of two or more parts" , "Combined" , "Made up of different elements" , "Motion" , "Formed of distinct parts" .)