black fly

American

noun

any of the minute, black gnats of the dipterous family Simuliidae, having aquatic larvae.

black fly British

noun

any small blackish stout-bodied dipterous fly of the family Simuliidae , which sucks the blood of man, mammals, and birds See also buffalo gnat

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of black fly

First recorded in 1600–10

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Spikes in black fly activity are often caused by scheduled water releases from upstream dams, which are necessary for the region’s water management but also create ideal breeding conditions for the pests.

From Los Angeles Times • Mar. 27, 2026

Between Barthes and Berlant, Alanis gets to have the black fly in her chardonnay and drink it, too.

From Salon • Nov. 29, 2024

Former Democratic presidential nominee Hillary Clinton famously saw a black fly land between her eyes during one of her debates against then-candidate Donald Trump.

From Fox News • Aug. 20, 2020

And in water, black fly larvae may use bristly fans to suspend themselves and filter food particles out of the water.

From New York Times • Oct. 23, 2018

The black fly flew unsteadily about the room.

From "Norse Mythology" by Neil Gaiman

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023