Get agreement on fixed terms (8)
I believe the answer is:
contract
This clue might be a double definition.
'get' is the first definition.
(I know that get can be written as contract)
'agreement on fixed terms' is the second definition.
'contract' can be an answer for 'agreement' (contract is a kind of agreement). I am not certain of the 'on fixed terms' bit.
Can you help me to learn more?
(Other definitions for contract that I've seen before include "Make smaller" , "Come down with" , "Binding agreement between two or more" , "Document setting out terms of agreement" , "Shorten" .)