Olympiad vs athletic contest

Olympiad and athletic contest both are nouns.

Word	Noun	Adjective	Verb	Adverb
Olympiad	Yes	No	No	No
athletic contest	Yes	No	No	No

As nouns, athletic contest is a hypernym of Olympiad; that is, athletic contest is a word with a broader meaning than Olympiad:

Olympiad: the modern revival of the ancient games held once every 4 years in a selected country
athletic contest: a contest between athletes

Other hypernyms of Olympiad include athletic competition, athletics.

Olympiad (noun)	athletic contest (noun)
the modern revival of the ancient games held once every 4 years in a selected country	a contest between athletes
one of the four-year intervals between Olympic Games; used to reckon time in ancient Greece for twelve centuries beginning in 776 BC