Tiny tick (6)
I believe the answer is:
minute
This clue is a double definition.
'tiny' is the first definition.
(minute can mean small)
'tick' is the second definition.
(thesaurus)
(Other definitions for minute that I've seen before include "Tiny like time unit (6)" , "Infinitesimal" , "Small; short time" , "Immeasurably small" , "60 seconds; tiny" .)