any one of numerous species of long-winged, migratory, orthopterous insects, of the family acrididae, allied to the grasshoppers; esp., (edipoda, / pachytylus, migratoria, and acridium perigrinum, of southern europe, asia, and africa. in the united states the related species with similar habits are usually called grasshoppers. see grasshopper.-the locust tree. see locust tree (definition, note, and phrases).