Any one of numerous species of voracious orthopterous insects of the genus Mantis, and allied genera. They are predacious long-bodied large-eyed insects of warm regions, are remarkable for their slender grotesque forms, and for holding their stout anterior legs in a manner suggesting hands folded in prayer. The common American species is Mantis Carolina. [1913 Webster]

Mantis shrimp. (Zoöl.) The Squilla, a tropical marine burrowing crustacean with large grasping appendages. Also called mantis crab and mantis prawn.

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OXFORD DICTIONARY

mantis, n. (pl. same or mantises) any insect of the family Mantidae, feeding on other insects etc.

Idiom

praying mantis a mantis, Mantis religiosa, that holds its forelegs in a position suggestive of hands folded in prayer, while waiting to pounce on its prey.

Etymology

Gk, = prophet

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