subsidiary
A subsidiary is a business that is wholly or partially owned by another business, sometimes called the parent company or holding company. The parent company owns sufficient voting stock in the subsidiary -- as a rule, at least 50% -- to give it control over the subsidiary's operations and management. In a wholly-owned subsidiary, the parent company owns 100% of the stock.
A parent company with subsidiaries is one type of conglomerate, which is a company that comprises multiple different businesses.