Note house beer's off around five (9)
I believe the answer is:
semibreve
'note' is the definition.
(musical note)
'house beer's off around five' is the wordplay.
'house' becomes 'semi' (semi-detached house).
'off' indicates an anagram.
'around' indicates putting letters inside.
'five' becomes 'V' (Roman numeral).
'beer' with letters rearranged gives 'bree'.
'bree' enclosing 'v' is 'breve'.
'semi'+'breve'='SEMIBREVE'
(Other definitions for semibreve that I've seen before include "2 minims/4 crotchets" , "Note equivalent to four crotchets" , "Note equal to two minims" .)