An improvement. / (law) An improvement to a property that adds to its value.

plural of betterment

continually improving

plural of betterness

(uncountable) The state or quality of being better; superiority. / (countable) The result or product of being better. / (minting) The amount by which a precious metal exceeds the standard of fineness.

(nonstandard) comparative form of better: more better / (nonstandard) better

One who betters, makes something better.

comparative degree of good / comparative degree of well / Greater in amount or quantity

comparative degree of well / Greater or lesser (whichever is seen as more advantageous), in reference to value, distance, time, etc. / (colloquial shortening) Had better.

(transitive) To improve. / (intransitive) To become better; to improve. / (transitive) To surpass in excellence; to exceed; to excel.