any bloodsucking, usually large fly of the family Tabanidae, especially of the genus Tabanus, a serious pest of horses, cattle, etc.
Origin of horse fly
1350–1400; Middle English horsfleeye
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for horsefly
Historical Examples of horsefly
A horsefly (hoane) lived there at the edge of the mesa in a cavity.
Tabanidae viridis was not sent just to plague us with horsefly bites.
As much human affection as you can squeeze out of the60 hind foot of a horsefly!
In spite of the humid atmosphere, a buzzing like that of a horsefly, hummed several times above the two visitors.
British Dictionary definitions for horsefly
noun plural -flies
any large stout-bodied dipterous fly of the family Tabanidae, the females of which suck the blood of mammals, esp horses, cattle, and manAlso called: gadfly, cleg
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for horsefly
late 14c., from horse (n.) + fly (n.).
Online Etymology Dictionary, © 2010 Douglas Harper