Definition of katydid

• n. - A large, green, arboreal, orthopterous insect (Cyrtophyllus concavus) of the family Locustidae, common in the United States. The males have stridulating organs at the bases of the front wings. During the summer and autumn, in the evening, the males make a peculiar, loud, shrill sound, resembling the combination Katy-did, whence the name.