cross-staff

[ kraws-staf, -stahf, kros- ]

/ ˈkrɔsˌstæf, -ˌstɑf, ˈkrɒs- /

noun, plural cross-staffs, cross-staves. Astronomy.

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.

Nearby words

cross-resistance, cross-section, cross-sectional study, cross-sell, cross-slide, cross-staff, cross-sterile, cross-stitch, cross-stratification, cross-string, cross-tolerance

Origin of cross-staff

1400–50, for an earlier sense; late Middle English

Also called forestaff, Jacob's staff.

Examples from the Web for cross-staff

The cross-staff had not then come into use, and it was never of much service in low latitudes.
Christopher Columbus and His Monument Columbia|Various
Even the navigators of the fifteenth century were aware of the deficiencies of the cross-staff and sought to improve upon it.
Every-day Science: Volume VII. The Conquest of Time and Space|Henry Smith Williams
The simplest and crudest form of measurer of which the record has been preserved is known as the cross-staff.
Every-day Science: Volume VII. The Conquest of Time and Space|Henry Smith Williams
Iacobs staffean instrument formerly used for measuring the altitude of the sun; a cross-staff.
The Fatal Dowry|Philip Massinger

The vane of a cross-staff, made to slide along it by means of a square socket; it may be set to any of the graduations.
The Sailor's Word-Book|William Henry Smyth