This is the 586th most frequent Portuguese word.
marcou
"Marcou" means "marked" or "scored" (past tense of "marcar").
Here, "marcou" is used in the sense of scoring, common in sports contexts.
Ele marcou um gol incrível na partida.
He scored an incredible goal in the match.
In this context, "marcou" is used to denote marking or noting down something.
Ela marcou o evento no calendário para se lembrar.
She marked the event on the calendar to remember.
Here, "marcou" is used metaphorically to signify an event having significant impact or importance.