At home, ready for inclusion (5)
'inclusion' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'at home ready' is the wordplay.
'at home' becomes 'in' (similar in meaning).
'ready' becomes 'set' (synonyms).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for inset that I've seen before include "Small picture inserted within a larger one", "Small piece inserted", "Photographic cameo superimposed on to another print", "Put (one thing) into (another)", "Picture inside a larger one".)