Cubes of frozen stuff applied to wound ultimately (4)
I believe the answer is:
dice
'cubes' is the definition.
(I have seen 'Small cubes ' mean 'dice' so perhaps 'cubes' could also mean 'dice')
'frozen stuff applied to wound ultimately' is the wordplay.
'frozen stuff' becomes 'ice' (ice is frozen water).
'applied to' says to put letters next to each other.
'ultimately' indicates one should take the final letters.
The final letter of 'wound' is 'd'.
'ice' after 'd' is 'DICE'.
'of' is the link.
(Other definitions for dice that I've seen before include "Gambling pieces" , "Cut into small cubes" , "Random number generators" , "Take a risk" , "Cubes used in gambling" .)