This is the 1993rd most frequent Portuguese word.
aparecer
To appear or to show up.
In this sentence, 'apareceu' means 'showed up,' indicating someone's arrival or presence.
Ele apareceu de repente na festa.
He showed up suddenly at the party.
Here, 'aparecer' is used figuratively to indicate the occurrence or emergence of something new.
Amanhã pode aparecer outra oportunidade.
Tomorrow another opportunity might arise.
In this context, 'aparecer' means 'to appear,' referring to something becoming visible.