The immensely useful and free encyclopaedia Wikipedia provides a clear definition of “skeuomorphism” (skeuos vessel or tool, morphe shape). A skeuomorph is a derivative object that retains ornamental design cues to a structure that was necessary in the original. Skeuomorphs may be deliberately employed to make the new item appear to be comfortably old and familiar, such as copper cladding on zinc coins, to make them look like old pennies, or computer printed postage with a circular town name and cancellation lines, meant to resemble the original circular stamps used by humans in post offices.
An alternative definition is “an element of design or structure that serves little or no purpose in the artifact fashioned from the new material but was essential to the object made from the original material”. This definition is narrower in scope and ties skeuomorphs to changes in materials.
The word is recently popular in English in 2012, I suspect because of the furore about Apple’s skeuomorphic designs for its ubiquitous computer software. See the little bit of torn paper just below the fake-leather strip across the head of the fake paper iCal calendar in the picture, just below the fake-embossed word “Year”? Torn paper? On a computer screen?!?! What were they thinking!?!?
But relax! The practice goes back to the birth of civilisation. Ancient Greek architecture abounds in skeuomorphism.
I like the Corinthian column, the capital (top) of which carries an ornate carved and originally painted stone representation of the acanthus leaf once used to decorate the top of the original wooden columns that long before had preceded the stone versions.
Egyptian columns, with their tops carved and painted to resemble plants abundant in the waters of the Nile — lilies or bundles of the lotus or the papyrus reed — were no doubt the inspiration for this later practice.
Wikipedia notes that blue jeans have authentic-looking brass rivet caps covering the functional steel rivet beneath; they further note that some digital cameras play a recorded audio clip of a conventional single-lens reflex camera mirror slap and shutter click. And so it goes.
I love these: they’re so silly! Tiny, non-functional handles on small glass maple syrup containers. The containers were once large earthenware jugs, which needed a handle. Not any more, but the handle still says “maple syrup”, even if the little bottle contains — yes, you need to take out your glasses and read the fine print — 99 per cent corn syrup.