Inc. & Co. & conglomerate 既分別

Inc. = Incorporated. This means a limited company. The name is used in overseas limited company.
Co. = Company. This means a firm ( Sole Proprietorship, Partnership) or a limited company in general term. However, if the company is a limited company, the name must be precisely stated as ABC Company Limited.
Conglomerate = a big company. The company is a very big group of companies with subsidiaries and associates with a very high sales volume, high value of assets and a big and complicated staff structure. Moreover, the group may have overseas subsidiaries or associates