1. A crucial point in time that has a significant impact on someone's life, career, or character, often determining future outcomes or establishing a lasting impression
Winning the championship was a defining moment in her athletic career.
Ganhar o campeonato foi um momento decisivo em sua carreira atlética.
2. A turning point that clearly reveals or establishes someone's true nature, values, or abilities
How he handled the crisis was a defining moment that showed his leadership qualities.
Como ele lidou com a crise foi um momento decisivo que mostrou suas qualidades de liderança.