Mutually

[myoo-choo-uh l] /ˈmyu tʃu əl/

adjective
1.
possessed, experienced, performed, etc., by each of two or more with respect to the other; reciprocal:
to have mutual respect.
2.
having the same relation each toward the other:
to be mutual enemies.
3.
of or relating to each of two or more; held in common; shared:
mutual interests.
4.
having or pertaining to a form of corporate organization in which there are no stockholders, and in which profits, losses, expenses, etc., are shared by members in proportion to the business each transacts with the company:
a mutual company.
See also .
noun
5.
Informal. a .
/ˈmjuːtʃʊəl/
adjective
1.
experienced or expressed by each of two or more people or groups about the other; reciprocal: mutual distrust
2.
common to or shared by both or all of two or more parties: a mutual friend, mutual interests
3.
denoting an insurance company, etc, in which the policyholders share the profits and expenses and there are no shareholders
adv.

1530s, from mutual + -ly (2). Mutually exclusive is recorded by 1650s.
adj.

late 15c., originally of feelings, from Middle French mutuel (14c.), from Latin mutuus “reciprocal, done in exchange,” from PIE root *mei- “to change, exchange” (see mutable).

The essence of its meaning is that it involves the relation x is or does to y as y to x; & not the relation, x is or does to z as y to z. [Fowler]

Mutual Admiration Society (1851) seems to have been coined by Thoreau. Mutual fund is recorded from 1950. The Cold War’s mutual assured destruction attested from 1966. (Assured destruction was an early 1960s term in U.S. military policy circles in reference to nuclear weapons as a deterrent, popularized c.1964 by Robert McNamara, U.S. Secretary of Defense under Lyndon Johnson, e.g. statement before House Armed Services Committee, Feb. 18, 1965; the mutual perhaps first added by Donald Brennan, conservative defense analyst and a public critic of the policy, who also noted the acronym MAD.)

n.

short for mutual fund, 1971; see mutual.