Olympics as a proper noun is the olympic games. while Olympiad as a noun is a period of four years, by which the ancient greeks reckoned time, being the interval from one celebration of the olympic games to another, beginning with the victory of corbus in the foot race, which took place in the year 776 b.c.; as, the era of the olympiads.
Part of speech: proper noun
Definition: The Olympic Games.
Part of speech: noun
Definition: A period of four years, by which the ancient Greeks reckoned time, being the interval from one celebration of the Olympic games to another, beginning with the victory of Corbus in the foot race, which took place in the year 776 b.c.; as, the era of the olympiads.
We hope you now know whether to use Olympics or Olympiad in your sentence.