Final answer:
A corporate merger or acquisition involves the combination or ownership transfer of two firms into a single entity. Mergers may be lateral, with similarly-sized companies joining forces. Nationalization and privatization are different processes, related to government control or the transfer of assets to private ownership respectively.
Step-by-step explanation:
A corporate merger occurs when two formerly separate firms combine to become a single firm, which can also be described as an acquisition if it involves one firm purchasing another. This can happen in scenarios where companies of similar sizes engage in a lateral merger, merging to increase their market power or achieve synergies. While an acquisition might result in the purchased company continuing to operate under its original name, the essence of both a merger and an acquisition is that they result in two formerly independent firms coming under common ownership.
It is important to note that this is distinct from nationalization, which is when a government takes control of an entity, transforming it from private to public ownership. In the context of privatization, this involves transferring government-owned businesses to individuals.