Maybe Avalon features in this legend (4)
I believe the answer is:
isle
'maybe avalon features in this legend' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'in this legend' is the wordplay.
'in' indicates a hidden word.
'ISLE' is hidden within 'this legend'.
Can you help me to learn more?
(Other definitions for isle that I've seen before include "Small bit of land surrounded by water" , "eg Man, Ely" , "one ringed in the main?" , "Small mass of land in the sea" , "eg Hoy, Yell or Sark" .)