This is the 9543rd most frequent Spanish word.
anunciarán
"Anunciarán" means "they will announce."
In this sentence, 'anunciarán' is used as the future tense of 'anunciar', indicating a planned or expected announcement.
Mañana anunciarán los ganadores del concurso.
Tomorrow they will announce the competition winners.
Here, 'anunciarán' is part of a subordinate clause expressing a condition in the future.
Cuando anunciarán la próxima fecha, por favor avísame.
When they will announce the next date, please let me know.
In this context, 'anunciarán' refers to a statement of intent communicated by an external source.