See merger in Webster's New World College Dictionary
noun
a merging; specif.,
☆ a combining of two or more companies, corporations, etc. into one, as by issuing stock of the controlling corporation to replace the greater part of that of the other or others
the absorption of one estate, interest, obligation, contract, etc. in another, or of a lesser offense in a greater
See merger in American Heritage Dictionary 4
(mûrˈjər)
noun
The act or an instance of merging; union.
The union of two or more commercial interests or corporations.
Law The absorption of a lesser estate, liability, right, action, or offense into a greater one.