A business combination is a transaction in which the acquirer obtains control of another business (the acquiree). Business combinations are a common way for companies to grow in size, rather than growing through organic (internal) activities.
A business is an integrated set of activities and assets that can provide a return to investors in the form of dividends, reduced costs, or other economic benefits. A business typically has inputs, processes, and outputs. A development-stage entity may not yet have outputs, in which case you can substititute other factors, such as having begun operations and having plans to produce output, and having access to customers who can purchase the outputs.
A business combination is not the formation of a joint venture, nor does it involve the acquisition of a set of assets that do not constitute a business.
When there is a business consolidation, the acquirer thereafter reports consolidated results that combine its own financial statements with those of the acquiree. The acquirer does not include in this consolidation the financial statements of the acquiree for any reporting periods prior to the acquisition date.