Underdren or Underdrain: How To spell?
The word Underdren is misspelled against Underdrain, a noun meaning "An underground drain or trench with openings through which the water may percolate from the soil or ground above."
The word Underdren is misspelled against Underdrain, a noun meaning "An underground drain or trench with openings through which the water may percolate from the soil or ground above."