| 释义 |
parallel motion protractor parallel motion protractor[′par·ə‚lel ¦mō·shən ′prō‚trak·tər] (graphic arts) An instrument consisting essentially of a protractor and one or more arms attached to a parallel motion device, so that the movement of the arms is everywhere parallel; the protractor can be rotated and set at any position so that it can be oriented to a chart. Also known as drafting machine. |