[kraws-staf, -stahf, kros-]
- an instrument for measuring the angle of elevation of heavenly bodies, consisting of a calibrated staff with another shorter staff perpendicular to and sliding on it.
Origin of cross-staff
1400–50, for an earlier sense; late Middle English
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018