'backswimmer' definitions:

Definition of 'backswimmer'

From: WordNet
noun
Predaceous aquatic insect that swims on its back and may inflict painful bites [syn: backswimmer, Notonecta undulata]

Definition of 'backswimmer'

From: GCIDE
  • backswimmer \back"swim`mer\ n. any of numerous predaceous aquatic insects of the family Notonectidae (such as Notonecta undulata) that swim on their backs and may inflict painful bites; -- also called boat bug. --[RHUD] [WordNet 1.5 +PJC]