A drop of ice (6)
I believe the answer is:
icicle
'ice' is the definition.
(I know that icicle is a type of ice)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for icicle that I've seen before include "Winter spike" , "Frozen water drip" , "Cold hanger" , "Hanging ice; stalactite" , "Hanging drop of cold water" .)