perpendicularis

Forms

perpendiculāris (neuter perpendiculāre, adverb perpendiculāriter); third-declension two-termination adjective^[1]

Etymology

It is formed from Latin perpendiculum (“plumb line”) + -āris.^[2][1] The base comes from perpendō (“to weigh carefully”).^[3]

Earliest recorded meaning

It first appears in the land surveyor Balbus (98–117),^[4] as a term of geometry for a line at right angles to another.^[2][5]

Semantic evolution

It remained a technical word of the Roman surveyors,^[6][5] mostly used for the perpendicular line itself, rendering Ancient Greek κάθετος (káthetos).^[5] Martianus Capella uses it too.^[5]

Medieval Latin geometry kept the sense of standing at right angles, as in Adelard of Bath's Euclid, and added that of vertical, at right angles to the earth's surface.^[7] Robert Grosseteste uses it as a noun for a perpendicular line.^[4] It is the source of Italian perpendicolare.^[8]

Timeline

• 98–117 AD – The surveyor Balbus uses it.^[4]
• 2nd century AD – Nipsus uses it in the surveyors' corpus.^[4][5]
• 1220–1235 – Robert Grosseteste uses it as a noun for a perpendicular line.^[4]
• late 15th century – Borrowed into English, through Old French, as perpendicular.^[3]

Meanings

Adjective

1. (geometry) At right angles to a line or plane, perpendicular.^[2][9]
2. (Medieval Latin) vertical, upright.^[7]

Noun

1. (Medieval Latin) A perpendicular line.^[4]

Related words

• perpendiculum
• English perpendicular

Usage notes

A second-declension form perpendiculārius is also recorded.^[9][10][8]

References

1. ^ a b c d Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
3. ^ a b Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e f Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
5. ^ a b c d e Thesaurus linguae Latinae (1900–), Leipzig: Teubner; Berlin: De Gruyter; open-access ed., Munich: Bayerische Akademie der Wissenschaften
6. ^ Georges, Karl Ernst (1913–1918), Ausführliches lateinisch-deutsches Handwörterbuch, 8th ed., ed. Heinrich Georges, Hannover; Leipzig: Hahn
7. ^ a b Latham, R. E., D. R. Howlett, R. K. Ashdowne, et al. (1975–2013), Dictionary of Medieval Latin from British Sources, London: British Academy / Oxford University Press
8. ^ a b Conte, Gian Biagio; Pianezzola, Emilio; Ranucci, Giuliano (2010), il Latino: Vocabolario della lingua latina, 3rd ed., Florence: Le Monnier
9. ^ a b Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
10. ^ Gaffiot, Félix (2016), Dictionnaire latin-français, new ed. by Gérard Gréco et al. (Gaffiot 2016), online ed.