Part of an ellipsis (3)
I believe the answer is:
dot
'part of an ellipsis' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for dot that I've seen before include "Full stop, point" , "scatter" , "Very small circular shape" , "Absolutely punctual, on it" , "One signal used in Morse code" .)