noun
assistant; adjunct; lieutenant
Refers to a person in a supporting role, often in an official or organizational context. The nuance is of a trusted aide or second-in-command rather than a mere helper.
彼は社長の補佐役として会社を支えている。
He supports the company as the president's right-hand man.
新しいプロジェクトでは、彼女が補佐役を務めることになった。
She has been appointed to serve as an assistant on the new project.
助手 is a more general term for an assistant, often used in academic or technical settings, whereas 補佐役 implies a higher-level, often organizational support role.
Compound of 補佐 (ほさ, 'assistance, aid') and 役 (やく, 'role, duty'). The word straightforwardly means 'assistant role' or 'person in an assisting capacity'.