Pointed shapes visible in strobe lighting (5)
I believe the answer is:
obeli
'pointed shapes' is the definition.
(plural of 'obelus', dagger-shaped symbol)
'visible in strobe lighting' is the wordplay.
'visible in' says the answer is hidden in the clue.
'OBELI' is hidden in the letters of 'strobe lighting'.
(Other definitions for obeli that I've seen before include "signs of publishing" , "printing symbols" , "Textual indicators" , "daggers drawn" , "Dagger symbols, reference marks in print" .)