Magic words are a form of verbal incantation used to cast spells or perform other magical feats. The most commonly known magic words are 'ABRACADABRA' (11 letters), 'CHARM' (5 letters), 'hocuspocus' (10 letters) and 'opensesame' (10 letters). These words have been used in literature, film, television, and other media for centuries, and are often associated with witches, wizards, and other magical characters.