[ fi-doo-shee-er-ee, -dyoo- ]
/ fɪˈdu ʃiˌɛr i, -ˈdyu- /

noun, plural fi·du·ci·ar·ies.

Law. a person to whom property or power is entrusted for the benefit of another.


Law. of or relating to the relation between a fiduciary and his or her principal: a fiduciary capacity; a fiduciary duty.
of, based on, or in the nature of trust and confidence, as in public affairs: a fiduciary obligation of government employees.
depending on public confidence for value or currency, as fiat money.

Origin of fiduciary

1585–95; < Latin fīdūciārius of something held in trust, equivalent to fīdūci(a) trust + -ārius -ary
Related formsfi·du·ci·ar·i·ly, adverbnon·fi·du·ci·ar·y, adjective, noun, plural non·fi·du·ci·ar·ies. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for fiduciarily


/ (fɪˈduːʃɪərɪ) law /

noun plural -aries

a person bound to act for another's benefit, as a trustee in relation to his beneficiary


  1. having the nature of a trust
  2. of or relating to a trust or trustee
Derived Formsfiduciarily, adverb

Word Origin for fiduciary

C17: from Latin fīdūciārius relating to something held in trust, from fīdūcia trust; see fiducial
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 fiduciarily



1630s, from Latin fiduciarius "(holding) in trust," from fiducia "trust" from root of fidere "to trust" (see faith). In Roman law, fiducia was "a right transferred in trust;" paper currency sense (1878) is because its value depends on the trust of the public. As a noun, from 1630s.

Online Etymology Dictionary, © 2010 Douglas Harper