Number initially brought down, such as four and six (5)
I believe the answer is:
evens
'number initially brought down such as four' is the definition.
I can't judge whether this definition defines the answer.
'and six' is the wordplay.
I cannot quite understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is located in the answer.
The remaining letters 'eves' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
(Other definitions for evens that I've seen before include "Bookies' odds matching the amount staked" , "Makes equal" , "In betting, winning the amount staked" , "Level odds?" , "50-50 chance" .)