Final answer:
A corporate merger involves two private firms joining together. An acquisition refers to one firm buying another firm. In either case, two formerly independent firms become one firm.
Step-by-step explanation:
A corporate merger occurs when two formerly separate firms combine to become a single firm. When one firm purchases another, it is called an acquisition.
An acquisition may not look just like a merger, since the newly purchased firm may continue to operate under its former company name.
Mergers can also be lateral, where two firms of similar sizes combine to become one. However, both mergers and acquisitions lead to two formerly separate firms operating under common ownership, and so they are commonly grouped together.