1. The act of taking on or beginning a new job, role, or official position
The assumption of position as CEO took place on January 1st.
A assunção do cargo de diretor executivo ocorreu em 1º de janeiro.
2. The formal taking over of duties and responsibilities in an official capacity
His assumption of position as ambassador was marked by a grand ceremony.
Sua assunção do cargo de embaixador foi marcada por uma cerimônia solene.