This is the 364th most frequent Portuguese word.
oficial
Official.
Here, 'oficial' is used as an adjective to qualify 'anúncio,' showing it is formal and authorized.
O anúncio oficial foi feito ontem.
The official announcement was made yesterday.
In this context, 'oficial' acts as a noun referring to a person holding an official position.
Ele é o oficial encarregado dessa missão.
He is the officer in charge of this mission.
Here, 'oficial' classifies 'cerimônia,' indicating that the event had a formal and authoritative nature.