A smiley, sometimes referred to as a smiley face, is a basic ideogram that represents a smiling face, which has become part of popular culture worldwide. In modern times, the smiley has mostly been known for its yellow face and has evolved from a simple smiling face to display a range of facial emotions. Drawings of smileys have been traced back to ancient times, often displayed in caves and were often just two eyes and a curved upwards mouth.
From wikipedia.org