Family gathering originally associated with US racket (8)
I believe the answer is:
clangour
'racket' is the definition.
(both can mean a loud noise)
'family gathering originally associated with us' is the wordplay.
'family' becomes 'clan' (clan can mean a large family).
'originally' suggests taking the first letters.
'associated with us' becomes 'our' ('our' is the possessive pronoun for 'us').
The first letter of 'gathering' is 'g'.
'clan'+'g'+'our'='CLANGOUR'
(Other definitions for clangour that I've seen before include "Loud ringing noise" , "Commotion" , "Uproar; loud repeated noise" , "Loud resounding noise" .)