Drop of water (3)
I believe the answer is:
ebb
This clue might be a double definition.
'drop' is the first definition.
(I've seen this in another clue)
'water' is the second definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for ebb that I've seen before include "Drain away; decline" , "Fall back" , "Outward flow of the tide" , "Tidal outflow" , "Withdraw heartless" .)