One of the four-year intervals between Olympic Games; used to reckon time in ancient Greece for twelve centuries beginning in 776 BC WordNet 3.0 & Open English WordNet

An olympiad is a period of four years, particularly those associated with the ancient and modern Olympic Games. Wikipedia

Period of four years associated with the Olympic Games of the Ancient Greeks Wikipedia Disambiguation

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 BC; as, the era of the olympiads. Wiktionary

Period of four years. Wiktionary (translation)

Olympic games. Wiktionary (translation)