ameliorate (v.)

1650s, "a making or becoming better," from French amélioration, from Old French ameillorer (12c.), from a "to" (see ad-) + meillior (Modern French meìlleur) "to better, repair, improve," from Late Latin meliorare "improve," from Latin melior "better," perhaps originally "stronger," from PIE root *mel- (2) "strong, great."

Proto-Indo-European root meaning "strong, great." It forms all or part of: ameliorate; amelioration; meliorate; melioration; meliorism; multi-; multiform; multiple; multiply; multitude. It is the hypothetical source of/evidence for its existence is provided by: Greek mala "very, very much;" Latin multus "much, many," melior "better."