Crossword Clue:

indefinitely short period of time instant

AnswerCrossword Clue
AEONAn indefinitely long period of time
SECShort period of time
MOMENTShort period of time
SECShort period of time: Colloq.
FUTURESHOCKResult of "too much change in too short a period of time" (Alvin Toffler)
SECTime period, for short