noun
founder; establisher; opener
Refers to the person or entity that establishes, opens, or sets up something such as a company, institution, facility, or account. Often used in formal or business contexts.
この学校の開設者は地元の教育委員会です。
The founder of this school is the local board of education.
口座の開設者本人が手続きを行ってください。
The account opener themselves must carry out the procedure.
創設者 implies a more creative or pioneering founding, often used for institutions, awards, or movements, whereas 開設者 is more neutral and administrative.
Compound of 開設 (kaisetsu, 'opening, establishment') + 者 (sha, 'person'). The word is transparently derived from its components.