merger

ot noun

1. The act or process of merging two or more parts into a single unit. Club mergers reduced the number of teams by half
2. One that merges.
3. The legal union of two or more corporations into a single entity, typically assets and liabilities being assumed by the buying party.
4. An absorption of one or more estate(s) or contract(s) into one other, all being held by the same owner; of several counts of accusation into one judgement, etc.