Correct fish found in a square (5,5)
I believe the answer is:
right angle
'a square' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'correct fish' is the wordplay.
'correct' becomes 'right' (right can mean correct).
'fish' becomes 'angle' (angle can mean to fish).
'right'+'angle'='RIGHT-ANGLE'
'found in' is the link.
Can you help me to learn more?
(Other definitions for right angle that I've seen before include "Ninety-degree corner" , "Perhaps where planes hit" , "Part of a square" , "That between perpendicular and base" , "Ninety degrees" .)