Merriam-Webster Collegiate Dictionary - interchange

 I. verb  Etymology: Middle English entrechaungen, from Anglo-French *entrechanger, from entre- inter- + changer to change  Date: 14th century  transitive verb  1. to put each of (two things) in the place of the other  2. exchange  intransitive verb to change places mutually  • ~r noun  II. noun  Date: 15th century  1. the act, process, or an instance of interchanging ; exchange  2. a junction of two or more highways by a system of separate levels that permit traffic to pass from one to another without the crossing of traffic streams