Fashion trends come and go, and often return after a time. But gimmicky fads quickly fall into obsolescence, losing appeal and falling out of sight — do you know anyone who still has a pet rock?
The word obsolescence is the noun form of the more common obsolete, meaning "something no longer used." Both words stem from the Latin obsolēscere, which means, logically enough, "to fall into disuse." Your phone or your car may be designed for obsolescence, meaning they are meant to stop working or go out of style so you'll buy a newer model. More amusingly, TV personality Art Linkletter once commented, "The four stages of man are infancy, childhood, adolescence, and obsolescence.”