Vertical integration is the merger of two industries that are at different steps of production, e.g. food producer and a chain of supermarkets. Integration in this manner with something ahead in production process and closer to end customer is known as forward integration.
Vertical integration can also be compared to horizontal integration, the merger of trades that are at the same step of production, such as two supermarkets, or two food manufacturers. Merger with back in supply chain process (for example food manufacturer’s merger with agri-farm) is called backward integration