A point in time (6)
I believe the answer is:
period
I believe this clue is a double definition.
'a point' is the first definition.
(I know that full point can be written as period)
'time' is the second definition.
(I know that period is a type of geologic time)
'in' acts as a link.
(Other definitions for period that I've seen before include "Era, epoch" , "Full stop or time interval" , "School session" , "Stop in America" , "Stretch of time" .)