Underdrain

1. v. t. To drain by forming an underdrain or underdrains in; as, to underdrain land.
2. n. An underground drain or trench with openings through which the water may percolate from the soil or ground above.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.