Inorganic growth is increase in revenue or earnings acquired through mergers and acquisitions — the "buy-and-build" model of adding companies to expand scale and reach. It grows the enterprise by purchase rather than through the performance of the existing operations.
Inorganic growth is set against organic growth for good reason: the two reflect different capabilities. Acquired revenue reflects a capital-allocation and integration decision, not necessarily an improvement in the underlying business. Crediting it as organic performance confuses a shopping budget with operating skill, which is why disciplined reporting keeps the two strictly apart.