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backswimmer

American  
[bak-swim-er] / ˈbækˌswɪm ər /

noun

  1. any of numerous predaceous aquatic hemipterous insects, of the family Notonectidae, that swim on their backs, and may inflict a painful bite if handled.


Etymology

Origin of backswimmer

First recorded in 1860–65; back 1 + swimmer ( def. )