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definitions

merger

[mur-jer]

noun

a statutory combination of two or more corporations by the transfer of the properties to one surviving corporation.
any combination of two or more business enterprises into a single enterprise.
an act or instance of merging.

Origin of merger

First recorded in 1720–30; merge + -er1
Related formsan·ti·merg·er, adjectivede·merg·er, nounpre·merg·er, adjectivepro·merg·er, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for demerger

demerger

noun

the separation of two or more companies which have previously been merged

merger

noun

commerce the combination of two or more companies, either by the creation of a new organization or by absorption by one of the othersOften called (Brit): amalgamation
law the extinguishment of an estate, interest, contract, right, offence, etc, by its absorption into a greater one
the act of merging or the state of being merged
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for demerger

merger

n.

1728 in legal sense, "extinguishment by absorption," from merge (v.), on analogy of French infinitives used as nouns (e.g. waiver). From 1889 in the business sense; not common until c.1926. General meaning "any act of merging" is from 1881.

Online Etymology Dictionary, © 2010 Douglas Harper
demerger in Culture

merger

The union of two or more independent corporations under a single ownership. Also known as takeovers, mergers may be friendly or hostile. In the latter case, the buying company, having met with resistance from directors of the targeted company, usually offers an inflated (overmarket) price to persuade stockholders of the targeted company to sell their shares to it. Such mergers often have been financed by junk bonds.

Note

Especially common in the 1980s, hostile takeovers have become highly controversial. Some contend that they bring needed infusions of capital and efficiency to the targeted company. Others argue that, having borrowed heavily to finance the merger, the buyer is forced to sell valuable assets of the targeted company to pay off its debt.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.