The term 'sound of laughter' can be represented by a variety of words, including 'PEAL' (4 letters), 'hah' (3 letters), 'haha' (4 letters), 'hoho' (4 letters), 'ROAR' (4 letters), 'TEHEE' (5 letters), and 'teehee' (6 letters). Each of these words is an onomatopoeia, which is a word that imitates or suggests the source of the sound it describes. The sound of laughter can be expressed in many different ways, from a light chuckle to a loud guffaw.