umbra versa

短语

发音

UK /ˈʌmbɹə ˈvɜːsə/

释义与例句

n.
  1. 1.

    On a shadow in the shape of a right triangle, the length of the shadow's edge opposite to a measured angle.

词源

First attested in Modern English in 1688, although the phrase was also used in Middle English by Geoffrey Chaucer (c. 1343–1400) in his Treatise on the Astrolabe; Latin: umbra (“shadow”) + versa (feminine nominative singular of versus, “turned”) = “turned shadow”; compare umbra recta.

来源：wiktionary