Skeuomorph

A skeuomorph or skeuomorphism (Greek: skeuos—vessel or tool, morphe—shape) is a derivative object which retains ornamental design cues to a structure that was necessary in the original. Skeuomorphs may be deliberately employed to make the new look comfortably old and familiar.

Skeuomorph on Wikipedia. Bookmarked because I’m always forgetting the word and have had need to refer to it twice in the past week.