ROLL is the instantaneous value of the angle between the reference plane and the horizontal, measured in an athwartship vertical plane. 橫搖以從左到右通過艦身的垂直面，量度參考面與水平面之間所形成的即時角度。
This fixture should be provided with a reference leveling surface, so that it can be kept level as the balance deflects. 這種裝置應該有一個水平基準面，以便在天平變形時能夠使之保持水平。
The grinding surface is also the positioning surface of the workpiece in centerless grinding. 摘要無心磨削中，工件的磨削麵就是工件的定位基準面。
