An unprintable character is one that cannot be printed or displayed by a program because it is not supported. Unprintable characters are commonly displayed as an unrecognizable character, such as a small block, question mark, underscore, or blank space. For example, in the image, the second link has a single quote that is not supported by the browser. Instead, it shows up as a black diamond with a white question mark.

Character, Garbage, Keyboard terms

  • Keyboard help and support.