| 释义 |
〔quadrant〕An early instrument for measuring altitude of celestial bodies, consisting of a 90° graduated arc with a movable radius for measuring angles.象限仪：用来测量天体纬度的一种早期工具，由一个有90度刻度的圆弧和一个用来测量角度的可移动的半径构成〔cyclometer〕An instrument that measures circular arcs.圆弧测定器：一种用于测定圆弧的仪器〔turn〕To change the position of by traversing an arc of a circle; pivot:绕过，转动：绕过一段圆弧改变位置；使绕枢轴转动： |