The Collaborative International Dictionary
Isthmian \Isth"mi*an\, a. [L. Isthmius, Gr. ?. See Isthmus.] Of or pertaining to an isthmus, especially to the Isthmus of Corinth, in Greece.
Isthmian games (Gr. Antiq.), one of the four great national festivals of Greece, celebrated on the Isthmus of Corinth in the spring of every alternate year. They consisted of all kinds of athletic sports, wrestling, boxing, racing on foot and in chariots, and also contests in music and poetry. The prize was a garland of pine leaves.
Wikipedia
Isthmian Games or Isthmia ( Ancient Greek: Ἴσθμια) were one of the Panhellenic Games of Ancient Greece, and were named after the Isthmus of Corinth, where they were held. As with the Nemean Games, the Isthmian Games were held both the year before and the year after the Olympic Games (the second and fourth years of an Olympiad), while the Pythian Games were held in the third year of the Olympiad cycle.
Usage examples of "isthmian games".
Ignore the myths that locate Glaucus's death at Iolchis or Theban Pontiae on the occasion of Jason's funeral games for Pelias: it happened at the regular Isthmian games, which in those days we called the Argonauts' Funeral Stakes in memory of the Pelian originals.