Definition of fiducial in US English:



  • (especially of a point or line) assumed as a fixed basis of comparison.

    • ‘These holes were identifiable in the subsequent sections and served as external fiducial points for locating corresponding microscopic fields in each section and for aligning image stacks.’
    • ‘Because speckle contrast was often low and filament overlap could also produce speckles, myosin tethers were used as fiducial marks for this study.’
    • ‘For the cell types that were compared directly, the same fiducial point was used.’
    • ‘Coordinates, measured by hand from the sheets and the paths, serving as linear sets of fiducial points, were then used to construct, using ‘O,’ polyalanine chains representing putative amino terminal strand dispositions.’
    • ‘Because the Medilog system had a low sampling rate, we used an algorithm of interpolation to refine the QRS-complex fiducial point, in order to improve the accuracy of R-wave recognition.’


Late 16th century: from late Latin fiducialis, from fiducia ‘trust’, from fidere ‘to trust’.