MELIORATION
amelioration, melioration, betterment
(noun) the act of relieving ills and changing for the better
melioration
(noun) the linguistic process in which over a period of time a word grows more positive in connotation or more elevated in meaning
improvement, melioration
(noun) a condition superior to an earlier condition; “the new school represents a great improvement”
Source: WordNet® 3.1
Etymology
Noun
melioration (countable and uncountable, plural meliorations)
Archaic form of amelioration.
Source: Wiktionary
Mel`io*ra"tion, n. Etym: [L. melioratio.]
Definition: The act or operation of meliorating, or the state of being
meliorated; improvement. Bacon.
Source: Webster’s Unabridged Dictionary 1913 Edition