retronym

A retronym is a type of neologism that provides a new name for an object or concept to differentiate its original form or version 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. Examples of retronyms are "acoustic guitar" (coined when electric guitars appeared), and analog watch to distinguish from a digital watch.