500 replaced by 1,000 in accounts functions (5)
I believe the answer is:
works
'functions' is the definition.
('work' can be a synonym of 'function')
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for works that I've seen before include "Functions" , "Acts: the > opera" , "Plants; operates" , "Employs physical or mental effort" , "Factory; has a job" .)