The New Dictionary of Cultural Literacy, Third Edition. 2002.
in medias res
(in MAY-dee-uhs, MEE-dee-uhs RAYS) In the middle of the action. Epics often begin in medias res. For example, the Odyssey, which tells the story of the wanderings of the hero Odysseus, begins almost at the end of his wanderings, just before his arrival home. In medias res is a Latinphrase used by the poet Horace; it means in the middle of things.