释义 |
Cross-staff
Cross´-staff`
n. | 1. | An instrument formerly used at sea for taking the altitudes of celestial bodies. | | 2. | A surveyor's instrument for measuring offsets. |
cross-staff
cross-staff[′krȯs ‚staf] (navigation) A forerunner of the modern sextant, used for measuring altitudes of celestial bodies, consisting essentially of a wooden rod with one or more perpendicular crosspieces free to slide along the main rod. Also known as forestaff; Jacob's staff. ThesaurusSeeJacob's staff |