any of numerous migratory short-horned grasshoppers that often travels in vast swarms through in warm and tropical areas parts of Asia and Africa, stripping them areas they pass through of all vegetation: genera Locusta and Melanophus: compare grasshopper
any of various hard-wooded trees, e.g. the carob
any of various hard-wooded trees of the pea family, e.g.:
the carob tree: Ceratonia siliqua
a tall N American tree with thorns and hanging clusters of fragrant white flowers: Robinia pseudoacacia
[Middle English from Latin locusta locust, crustacean; (sense 2) from the pods allegedly resembling locusts]