bio·​swale | \ ˈbī-(ˌ)ō-ˌswāl How to pronounce bioswale (audio) \
plural bioswales

Definition of bioswale

: a long, channeled depression or trench that receives rainwater runoff (as from a parking lot) and has vegetation (such as grasses, flowering herbs, and shrubs) and organic matter (such as mulch) to slow water infiltration and filter out pollutants The new plan for Fordham Plaza is designed to be environment friendly, including such elements in the redesign as bioswales to mitigate storm water runoff, solar panels, and a small wind turbine.New York Construction, 1 Nov. 2010 Planted with vegetation suited to boggy conditions, the bioswales act like miniature wetlands that filter out—and biodegrade—the toxins contained in the runoff.— Anita Marks, Business Journal-Portland, 18 Nov. 1994

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

First Known Use of bioswale

1994, in the meaning defined above

History and Etymology for bioswale

bi- entry 2 + swale

Keep scrolling for more

Learn More about bioswale

Time Traveler for bioswale

Time Traveler

The first known use of bioswale was in 1994

See more words from the same year

Statistics for bioswale

Cite this Entry

“Bioswale.” Dictionary, Merriam-Webster, Accessed 4 Dec. 2020.

Comments on bioswale

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


Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
Spell It

Can you spell these 10 commonly misspelled words?

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!