I recently came across a word I had not previously heard of : retronym. With my linguistics background and the everyday familiarity of synonyms, homonyms, and antonyms, I was surprised that I had never heard this word.
A retronym is defined by Merriam-Webster as "a term consisting of a noun and a modifier which specifies the original meaning of the noun."
Answers.com adds a bit more detail to their definition by explaining that a retronym is "a word or phrase created because an existing term that was once used alone needs to be distinguished from a term referring to a new development, as acoustic guitar in contrast to electric guitar or analog watch in contrast to digital watch."
In addition to the guitar and watch examples here are some more retronyms to think about:
Brick-and-mortar store, high street shop
George H.W. Bush
Turn based strategy
I guess we have technology to thank for retronymy.