noun

• (heraldry) An escutcheon or ensign armorial; a full display or depiction of all the heraldic components to which the bearer of a coat of arms is entitled; (now especially) a funeral shield: the hatchment.
  "The narrow Gothic windows were filled, not with glass that admitted the light, but with glass painted with the achievements of the family […]."
• (video games) An award for completing a particular task or meeting an objective in a video game.
  "Finishing the game does not give you a 100% score until you have unlocked all of the achievements."
• (grammar, semantics) The lexical aspect (aktionsart) of verbs or predicates that change in an instant.
  "[…]distinctions among states of affairs are reflected to a striking degree in distinctions among Aktionsart types. That is, situations are expressed by state verbs or predicates, events by achievement verbs or predicates, and actions by activity verbs or predicates."
• (sociology) The successful completion of a socially defined goal or task, highlighting individual or group accomplishment.