from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of various aquatic bugs of the family Notonectidae that swim on their backs by means of broadened, oarlike hind legs.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of various aquatic insects, of the family Notonectidae, that swim on their backs.
from the GNU version of the Collaborative International Dictionary of English
- 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.
from The Century Dictionary and Cyclopedia
- n. Same as boat-fly.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. predaceous aquatic insect that swims on its back and may inflict painful bites
back + swimmer (Wiktionary)