In his travels, he wrote notes (5)
I believe the answer is:
ravel
'he wrote notes' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'in his travels' is the wordplay.
'in' indicates a hidden word.
'RAVEL' is hidden within 'his travels'.
Can you help me to learn more?
(Other definitions for ravel that I've seen before include "Tangle or become tangled" , "Make more complicated - French composer, d. 1937" , "He scored" , "Musician" , "Bolero's composer" .)