A member of a council or board who gives advice or makes decisions, often in a business, legal, or organizational context. The term is somewhat formal and not an everyday word.
He was elected as a trustee of the company.
The council meeting will be held next week.
評議員 is a similar term for a councilor or trustee, often used in educational or non-profit organizations. 商議員 is more associated with commercial or business councils.
Compound of 商 (commerce, business) and 議員 (member of an assembly). The term refers to a member of a commercial or business council.