Group having row secures agreement? That makes sense (8)
I believe the answer is:
eyesight
'sense' is the definition.
(eyesight is a kind of sense)
'group having row secures agreement?' is the wordplay.
'group having row' becomes 'eight' (an eight is a type of rowing crew).
'secures' means one lot of letters goes inside another.
'agreement?' becomes 'yes'.
'eight' going around 'yes' is 'EYESIGHT'.
'that makes' acts as a link.
(Other definitions for eyesight that I've seen before include "Power of seeing" , "Yes, eight required for vision" , "What's needed to see" , "Seeing ability" , "Ability to see" .)