fə̇ˈd(y)üshəl, fīˈ- adjective
Etymology: Late Latin fiducialis, from Latin fiducia + -alis -al
1. : founded on faith or trust
his fiducial reliance on certain religious beliefs
2. : having the nature of a trust : fiduciary
a fiducial power
3. : taken as an origin or zero of reference
a fiducial point on a scale
• fi·du·cial·ly -əlē adverb