| 词源 |
protractor n.1610s, "one who lengthens (an action)," Modern Latin agent noun from Latin protrahere "to draw forward" (see protraction). Medieval Latin protractor meant "one who calls or drags another into court." The surveying sense of "instrument for measuring and drawing angles on paper" is recorded from 1650s. As "muscle which serves to extend a limb or member," by 1861. updated on December 27, 2020 |