OED anyone?

A "retronym" is a term created to clarify an existing word rendered obsolete by advances in technology or changes in social practice.

When I was in California recently I challenged the mountain people to come up with as many retronyms as they could - Lisa was a savant with this by the way. I think it's a fun way to pass the time when the present isn't good for much more than the passing. Here are a few to get you started:

Acoustic guitar
Organic food
Snail mail
Summer Olympics
Free-range chickens
Coca Cola Classic
Traditional marriage

I used this in an introduction to a sermon I preached recently in which I attempted to explain the prevalence of the retronym "personal relationship" in Christian conversation and literature that discusses our relationship with God. It's a term made necessary by philosophical movements such as the enlightenment which savaged the personality of God reducing our Creator to little more than a force. I, at least, thought it was interesting - and that's the only goal I have in preaching - to keep myself awake.