| 释义 |
† ˈback-ˌstaff Obs.
[f. back n.]
A peculiar kind of quadrant formerly used in taking altitudes at sea, so called because the observer turned his back to the sun.
1627Capt. Smith Seaman's Gram. xv. 73 A Crosse staffe, a Backestaffe, an Astrolobe. 1696in Phillips; in mod. Dicts. |