A retronym is a new word or phrase coined for an old object or concept whose original name became used for something else. A lot of these are created by advances in technology. Some examples:
Black-and-white television: Once called simply television, now the retronym is used to distinguish it from color television, which is now more commonly referred to by the unadorned term. Along the same lines: broadcast television, silent movie.
Rotary-dial telephone: The kind of telephone in common use before touch-tone telephones.
Live poker: What casinos call the kind of poker played with cards by people sitting at a table; what many others still just call "poker". The term became necessary to distinguish it from video poker, which is far more common in casinos today.
Day baseball: Baseball played during the day, as all games were played before electric lighting in stadiums became common.
Brick-and-mortar store: A store with a building that customers can visit to examine its goods (which others might purchase at an online store[?]).
Face-to-face conference: A conference, not involving telephones or video cameras (similarly:IRL-meeting = in-real-life meeting).
French franc: The currency unit of France before the Euro, which was originally the only franc, but had to be distinguished from the Belgian franc, Communauté Financière Africaine franc, and Swiss franc after those countries adopted it.
Hot chocolate: In the days before the invention of sweet solid chocolate for eating, the word "chocolate" was usually used to refer to the drink; references to it in, say, Jane Austen's novels are confusing to the 21st century eye. For a while after the chocolate bar was invented it was referred to as "bar chocolate", but due to its stunning rise in popularity in the latter half of the 19th century it eventually laid claim to the basic word.
Pocket watch: Before the advent of the wristwatch, the word watch referred to watches carried in the pocket. After the advent of the wristwatch, the word watch referred to a watch worn on the wrist.
Analog watch: Before the advent of the digital watch, all watches had faces and hands. After the advent of the digital watch, watches with faces and hands became known as analog watches.
Some larger groupings include:
Conventional or Traditional X: For example, conventional (non-microwave) oven.