1. A date of personal importance or emotional significance to an individual, such as a birthday, anniversary, or commemorative date
Your anniversary is a significant date for you that deserves to be celebrated.
Seu aniversário é uma data significativa para você que merece ser celebrada.
2. A date that holds special meaning or relevance in someone's personal life or history
We should mark that date as it's significant for you.
Devemos marcar essa data pois é significativa para você.