Breath of wind over top of prairie (4)
I believe the answer is:
gasp
'breath' is the definition.
(I've seen this before)
'wind over top of prairie' is the wordplay.
'wind' becomes 'gas' ('gas' can be a synonym of 'wind').
'over' means one lot of letters go next to another.
'top of' indicates taking the first letters.
The first letter of 'prairie' is 'p'.
'gas'+'p'='GASP'
'of' is the link.
(Other definitions for gasp that I've seen before include "Pant" , "Utter breathlessly" , "Convulsive breath" , "Sudden intake of breath" , "Struggle for breath with open mouth" .)