improvement
n. C / Un. the process of making something better or the state of being better than before. You use it when a situation, skill, or object has changed for the better.
n. the act or process of enhancing the quality, value, or condition of something; a change that results in a superior state.
There is a big improvement in your English skills.
The city saw a significant improvement in air quality after the new environmental laws were passed last year.
While the initial results were promising, the engineering team noted that further improvement in battery efficiency would be necessary before the product could be released to the general public.
From Anglo-Norman emprouwement. By surface analysis, improve + -ment.
Uncountable when referring to the general process of getting better; countable when referring to a specific instance or change.
I made an improvement of my gradesI made an improvement in my gradesWhen referring to the area that has become better, the noun typically takes the preposition 'in' rather than 'of'.