swale

noun6

1. •
   A low tract of moist or marshy land.
2. •
   A long narrow and shallow trough between ridges on a beach, running parallel to the coastline.
3. •
   A shallow troughlike depression created to carry water during rainstorms or snow melts; a drainage ditch.
4. •
   Bioswale, a shallow trough dug into the land on contour (horizontally with no slope), whose purpose is to allow water time to percolate into the soil.
5. •
   A shallow, usually grassy depression sloping downward from a plains upland meadow or level vegetated ridgetop.

   • Jane climbed a few more paces behind him and then peeped over the ridge. Just beyond began a shallow swale that deepened and widened into a valley, and then swung to the left. — 1912
6. •
   (dialect, UK) A gutter in a candle.

noun1

1. •
   A strait between the Isle of Sheppey and the Kentish mainland; in full, The Swale.