black·​fly | \ ˈblak-ˌflī How to pronounce blackfly (audio) \
plural blackflies or blackfly

Definition of blackfly

: any of various small dark-colored insects especially : any of a family (Simuliidae and especially genus Simulium) of bloodsucking dipteran flies whose larvae usually live in flowing streams

Examples of blackfly in a Sentence

Recent Examples on the Web

Bug Shirt Untreated loose-knit fabrics provide no defense from mosquitoes, blackflies, and ticks. Andrew Skurka, Outside Online, "How to Pack for a Hike," 21 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'blackfly.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of blackfly

15th century, in the meaning defined above

Keep scrolling for more

Learn More about blackfly

Statistics for blackfly

Look-up Popularity

Time Traveler for blackfly

The first known use of blackfly was in the 15th century

See more words from the same century

Keep scrolling for more

More Definitions for blackfly



English Language Learners Definition of blackfly

: a small fly that bites


black·​fly | \ ˈblak-ˌflī How to pronounce blackfly (audio) \
plural blackflies

Medical Definition of blackfly

: any of a family (Simuliidae) and especially genus Simulium of bloodsucking dipteran flies

More from Merriam-Webster on blackfly

Rhyming Dictionary: Words that rhyme with blackfly

Comments on blackfly

What made you want to look up blackfly? Please tell us where you read or heard it (including the quote, if possible).


to take the place or position of

Get Word of the Day daily email!

Test Your Vocabulary

Words for Summer: A Quiz

  • a closeup of a sunflower
  • Which of the following words means “of or relating to summer”?
True or False

Test your knowledge - and maybe learn something along the way.

Syn City

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!