Accounting term that finally defines how we record time (3)
I believe the answer is:
gmt
'time' is the definition.
(I know that GMT is a type of time)
'accounting term that finally' is the wordplay.
'finally' says to take the final letters.
The last letters of 'accounting term that' are 'GMT'.
'defines how we record' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for gmt that I've seen before include "International reference time-scale" , "Global time standard" .)