corporate headquarters; business division; group
Refers to the main administrative office or a major business unit within a company. Often used in corporate names and organizational structures.
Our company's headquarters is in Tokyo.
A new business division has been launched.
本社 is the more common word for 'head office' or 'headquarters' of a company. 事業本部 often implies a specific business unit or a larger corporate headquarters with operational functions.
Compound of 事業 (business, enterprise) and 本部 (headquarters, main office).