fi·​du·​cial fə-ˈdü-shəl How to pronounce fiducial (audio)
: taken as standard of reference
a fiducial mark
: founded on faith or trust
: having the nature of a trust : fiduciary
fə-ˈdü-shə-lē How to pronounce fiducial (audio)

Example Sentences

Recent Examples on the Web The platform’s position, orientation, and velocity are estimated by an extended Kalman filter using simulated GPS measurements when the quadrotor-platform distance is large, and by a visual fiducial system when the platform is nearby. IEEE Spectrum, 13 Mar. 2020 Printed fiducial markers are inexpensive, easy to deploy, robust, and deservedly popular. IEEE Spectrum, 2 Dec. 2022 But Facebook is claiming that its system will work more smoothly and consistently than other AR platforms, and that will be simple for people to turn their posters or images into fiducial markers. Adi Robertson, The Verge, 5 Apr. 2018 A small camera on the headset was reading the fiducial markers on the (real) wall and using that spatial information to track his position among the (virtual) cubes. Peter Rubin, WIRED, 20 May 2014

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'fiducial.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


borrowed from Medieval Latin fīdūciālis "confident, trusting, trustworthy," going back to Late Latin, "having trust in God or the Christian faith," from Latin fīdūcia "trust, reliance, confidence" + -ālis -al entry 1 — more at fiduciary entry 1

First Known Use

1571, in the meaning defined at sense 1

Time Traveler
The first known use of fiducial was in 1571

Dictionary Entries Near fiducial

Cite this Entry

“Fiducial.” Dictionary, Merriam-Webster, Accessed 31 May. 2023.

Last Updated: - Definition revised
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