A retronym is a renaming necessitated by radical changes to the original technology or to significant technological advances. It comes from retro-, going back, and –nym, a form for name. In this case, examples will be useful.
•Acoustic guitar became necessary after the invention of the electric guitar.
•In earlier times, all clocks had moving hands to signify hours and minutes. When the digital clock was invented, the original was renamed an analog clock.
•When buttons appeared on telephones, earlier phones were designated as dial phones or rotary dial phones to distinguish them.
•And when traditional mail began to be supplanted by email, it was cruelly dubbed snail mail.
•At one point, computer disks were square and could be bent. When hard CD ROMs were ushered in, the originals were renamed floppies or floppy disks.
•Manual typewriter was unnecessary until the introduction of the electric typewriter. Now that’s been supplanted by the word processor and Lord knows what else.
•With the introduction of high definition TV, the older version was referred to as standard definition.
•Gas and electric grills made it necessary to distinguish wood-burning grills or charcoal grills.
•When sales became normal on the internet, the term brick-and-mortar stores appeared.
•Sharing the same sort of relationship are cyberspace and meatspace.
•When inventions to record music came along, we needed the term live music.
•When scanners were invented, copies printed on paper became hard copies
-- Michael Sheehan, Wordmall