A retronym is a new name for an object or concept to differentiate the original form or version of it from a more recent form or version. The original name is most often augmented with an adjective (rather than being completely displaced) to account for later developments of the object or concept itself. Much retronymy is driven by advances in technology.
Phrases/ words like: snail mail, tap water, film camera, silent film, manual typewriter, rotary dial phone,cloth diapers, biological parents, natural childbirth, hardcover, and even offline evolved after new words were needed to define the old from the new. I think this is one of the most interesting things I have ever heard of while watching Jeopardy, the game show on TV.
Can you think of a few other retronyms, without looking online? Just think back in history to changes in our technology, including the way we get from place to place, cook things, not just computers and communication (which probably have the most retronym words I can think of).
Wikipedia has a list of retronymns.