Wavelet (6)
I believe the answer is:
ripple
'wavelet' is the definition.
(I know that wavelet can be written as ripple)
This is all the clue.
(Other definitions for ripple that I've seen before include "Type of ice cream with coloured syrup" , "Slight disturbance on water's surface" , "Small wave or surface disturbance" , "Tiny wave; gentle applause" , "Small wave on a liquid's surface" .)