lightening
noun/ˈlaɪ.tn̩.ɪŋ/
1
The act or result of making something light or lighter.
- Bradly did not think of Cora till he picked up her figure ahead of him on the downs, but with that he was aware of a sudden lightening of his spirits, and stepped out faster to overtake her.1938, Norman Lindsay, Age of Consent, 1st Australian edition, Sydney, N.S.W.: Ure Smith, published 1962, →OCLC, page 134:
2
Medicine, Sciences The sensation caused by the descent of the uterus into the pelvic cavity before the onset of labour