umbra recta

Meaning

Noun

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

Related

Similar words

• umbra extensa

Origin

• 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 + rēcta (feminine nominative singular of rēctus, “straight”) = “straight shadow”; compare umbra versa.