Working at great races (7)
I believe the answer is:
regatta
'working' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'at great races' is the wordplay.
'races' is an anagram indicator (I've seen 'racing' mean this (to race around can mean to move)).
'at'+'great'='atgreat'
'atgreat' is an anagram of 'REGATTA'.
Can you help me to learn more?
(Other definitions for regatta that I've seen before include "Meeting for boat races" , "Boat-racing meeting" , "Display of boats" , "Sailing races" , "competition between banks" .)