Meaning of in medias res*

in me•di•as res

Pronunciation: (in me'di-äs" res' Eng. in mē'dē-&schwas" rēz', in mā'dē-äs" rās'), [key]
— Latin. Latin.
  1. in the middle of things.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.