merger (n.)

1728 in legal sense, "extinguishment by absorption," originally of real estate titles, from merge (v.), on analogy of French infinitives used as nouns (see waiver). From 1889 in the business sense "extinguishment of a security for a debt by the creditor's acceptance of a higher security;" not common until c. 1926. General meaning "any act of merging" is by 1881.