1. Having faith or trust; confident; undoubting; firm. Fiducial reliance on the promises of god.
2. Having the nature of a trust; fiduciary; as, fiducial power.
(Science: astronomy) fiducial edge, the straight edge of the alidade or ruler along which a straight line is to be drawn.
(Science: mathematics) fiducial line or point, a line or point of reference, as for setting a graduated circle or scale used for measurments.
Origin: L. Fiducia trust, confidence; akin to fides faith. See Faith.