Olympic adj.

high mountain in Thessaly, in Greek mythology the abode of the twelve greater gods, from Greek Olympos, a name of unknown origin. The name was given to several mountains and mountain ranges in Greece and the Near East. Beekes speculates that it originally meant "mountain" and is "without a doubt Pre-Greek."

"period of four years" (between Olympic games), late 14c., from Old French olimpiade "period of four years," from Latin Olympiadem, from Greek olympiados, genitive of Olympias "Olympian, of or pertaining to Olympus," an epithet of the muses, as a noun, "the Olympic games; a victor at Olympia; the space of four years between the celebrations of the Olympic games"(see Olympic). Used by ancient Greeks as a unit in computing time. Revived in modern usage with revival of the games, 1896. Related: Olympiadic.

To turn an Olympiad into a year B.C, multiply by 4, add the year of the Olympiad less 1, and subtract from 780. [Century Dictionary]

"of or belonging to Olympus," the mountain in Thessaly fabled to be the seat of the gods, c. 1600; see Olympus + -ian. The noun meaning "one of the twelve greater god of ancient Greece" is attested from 1843, from Late Latin Olympianus, from Greek Olympios "pertaining to Olympus." The sense of "one who competes in the (modern) Olympic Games" is from 1976 (see Olympic).