retronym

[re-truh-nim]
noun
  1. a term coined in modification of an original term that was used alone (as acoustic guitar instead of guitar ) to distinguish it from a term referring to a later development (as electric guitar ). Other examples of retronyms are snail mail and analog watch.

Origin of retronym

1980, Americanism; retro- + (-o)nym; coined by Frank Mankiewicz, U.S. journalist
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018