Quiet attempt to encapsulate Old English verse (6)
I believe the answer is:
poetry
'verse' is the definition.
(synonyms)
'quiet attempt to encapsulate old english' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'attempt' becomes 'try' (synonyms).
'to encapsulate' indicates putting letters inside.
'old english' becomes 'oe'.
'p'+'try'='ptry'
'ptry' going around 'oe' is 'POETRY'.
(Other definitions for poetry that I've seen before include "Literary art" , "'The Raven'?" , "Literature in metrical form" , "Literary genre" , "Lines" .)