1Originally: = "locust". In later use: specifically any of the large, grasshopper-like orthopteran insects constituting the genus Locusta; specifically the migratory locust, L. migratorius. Also (in form Locusta): the genus itself.
The genus Locusta is now limited to a single species, the migratory locust (L. migratorius).
2 historical A lobster, crayfish, or other crustacean. Compare "locust". rare.
Late Middle English; earliest use found in John Trevisa (c1342–?1402), translator. From classical Latin locusta locust.