This is the 1950th most frequent Spanish word.
serían
"Serían" means "they would be" or "you (plural) would be" in English.
In this sentence, 'serían' is used for expressing a hypothetical responsibility or role, indicating a conditional mood.
Ellos serían los encargados de organizar la fiesta.
They would be in charge of organizing the party.
Here, 'serían' indicates a tentative estimation of time, reflecting a conjecture or assumption in the past.
Serían las tres de la tarde cuando salí de casa.
It would have been three in the afternoon when I left home.
In this case, 'serían' conveys a future action, indirectly reported or referenced, illustrating a reported speech scenario.