The term was coined in 1964 by American cartoonist Mort Walker, who is best known as the creator of the Beetle Bailey and Hi and Lois cartoons.
He also created and named an international set of symbols used in comics around the world and called it Symbolia. A few examples:
briffits: clouds of dust indicating that a character left in a rush
plewds: drops of sweat indicating that a character is hot or stressed
squeans: asterisks with an empty center indicating drunkenness or dizziness