IPA: /əˈtʃiːvmənt/
KK: /əˈtʃivmənt/
A thing that has been done successfully, especially through hard work, skill, or determination.
Winning the championship was a significant achievement for the team.
Achievement → It is formed from "achieve" (from Old French *achever*, meaning to complete or bring to a conclusion) and "-ment" (a suffix used to form nouns indicating an action or resulting state). The word "achievement" refers to the state of having successfully completed or accomplished something.
Think of 'completing' something ('achever') and the '-ment' indicating a state — that's why achievement means the state of having accomplished something.