umbra recta

UK/ˈʌmbɹə ˈɹɛktə/

noun

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

Similar
umbra extensa

Meanings

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

    Scheubelius a great Mathematician, but by book only, and not by practice who being required ſometime in an Army to make uſe of his Quadrant, knew not the difference between umbra recta, and umbra verſa.

    1688, John Hales, “The Rich man’s Recepiſti”, in Golden Remains, 3rd edition, page 77

    Synonyms: umbra extensa

Synonyms & antonyms

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

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

Full word history & related roots →
Cite this entry
APA

umbra recta. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/umbra%20recta

MLA

“umbra recta.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/umbra%20recta. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “umbra recta,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/umbra%20recta.

Source: umbra recta on Wiktionary, CC BY-SA 4.0.