PLANATION
Meaning of PLANATION in English
/play nay"sheuhn, pleuh-/ , n. Geol.
the process whereby an irregular land surface is made flat or level by erosion.
[ 1875-80; PLANE 1 + -ATION ]
Random House Webster's Unabridged English dictionary.
Полный английский словарь Вебстер - Random House .
2012