Keycap

A keycap is a small plastic cover placed over the keyswitch of a computer keyboard. Keycaps are illustrated to indicate the key function or alphanumeric character they correspond to. Early keyboards were manufactured with the keyswitch and keycap integrated in one unit; separate keycaps were introduced to facilitate the production of different keyboard layouts.
Typical keycaps of the 1970s and 1980s were produced using two-shot molding, with the markings molded into each keycap in a different color of plastic, but this eventually fell out of favor, as it was more expensive (particularly in tooling costs), and tended to produce keycaps more durable than the equipment on which they were mounted. Modern keycaps are usually labelled by stamping or laser engraving.
There exist blank keycaps. These promote touch typing and help build muscle memory because the user can’t "cheat" by looking down at the keyboard. A notable keyboard to use blank keycaps is the Das Keyboard...