Meaning of lightening

light•en•ing

Pronunciation: (līt'n-ing), [key]
— n. Med.
  1. the descent of the uterus into the pelvic cavity, occurring toward the end of pregnancy, changing the contour of the abdomen and facilitating breathing by lessening pressure under the diaphragm.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
See also: