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

Word History


bi- entry 2 + swale

First Known Use

1994, in the meaning defined above

Time Traveler
The first known use of bioswale was in 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!

Dictionary Entries Near bioswale

Cite this Entry

“Bioswale.” Dictionary, Merriam-Webster, Accessed 21 Jul. 2024.

Love words? Need even more definitions?

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