(1) Lessen, let up, subside, reduce or be lessened, reduced, as to abate the rent by $100;
(2) to demolish, destroy, as to abate a condemned building;
(3) (Law) to put an end to, render null and void, as to abate a writ in court.
Usage: This word was brought to mind by a misuse of it heard recently in a TV news story on a storm: "the storm will ameliorate." While weather can get better, it is not clear what "the storm will ameliorate" (the storm will get better) could possibly mean: it will become a better storm? It will get stormier? Does this mean that its unhealthy condition will improve? Weather ameliorates; storms abate. The noun for today's word is "abatement."
Suggested Usage: Today's word may be used transitively or intransitively, so the weeds in your garden may abate on their own but, if they don't, you may abate them yourself with an appropriate herbicide. Anything fast, powerful, or uncontrollable may abate, "M. T. Head set out on a world-class shopping spree that did not abate until she had leveled the raised print on her credit card." (The downtown stores were offering price abatements across a wide range of goods and products.)