1. An individual's best performance or achievement in a particular activity or sport, typically a time or score that surpasses all previous attempts
She ran a personal best of 10.5 seconds in the 100-meter dash.
Ela correu um recorde pessoal de 10,5 segundos nos 100 metros rasos.
2. The highest standard or quality someone has achieved in any endeavor
This project represents my personal best work.
Este projeto representa o meu melhor trabalho pessoal.