circinus

Forms

circinus m (genitive circinī); second declension^[1]

Etymology

The OLD, the TLL and Wiktionary derive it from Latin circus (“circle”) + -īnus.^[2][3][1] Lewis & Short and Köbler instead equate it with Ancient Greek κίρκινος (kírkinos, “pair of compasses”),^[4][5] which Köbler connects with κίρκος (kírkos, “circle, ring”).^[5]

Isidore explained the name from the circle it draws when it is turned, and reported a derivation from Circinus, a name some gave to Daedalus' nephew instead of Perdix.^[3][6]

Earliest recorded meaning

Caesar, in the Gallic War, says that the river Dubis surrounds almost the whole town as if its course had been drawn with compasses.^[4][5]

Semantic evolution

Vitruvius uses it for drawing and measuring, and the phrase ad circinum for “in a circle, in an arc”;^[2][4] Pliny the Elder speaks of the ratio circini, the method of the compasses.^[4] The surveyor Balbus uses it for a circular line or arc.^[2] Glosses often treat it as a neuter, circinum.^[3]

Timeline

• c. 50 BC – Caesar compares the course of a river to a line drawn with compasses.^[4][5]
• c. 84–c. 25 BC – Vitruvius uses ad circinum, “in a circle”.^[2][5]
• 23/24–79 AD – Pliny the Elder speaks of the method of the compasses.^[4][5]
• c. 560–636 AD – Isidore explains the name from the circle it draws.^[3][5]

Meanings

Noun

1. A pair of compasses.^[2][4]
2. ad circinum: in a circle or arc.^[2]
3. A circular line or arc.^[2]

Word family

• circinō

References

1. ^ a b c d Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
3. ^ a b c d Thesaurus linguae Latinae (1900–), Leipzig: Teubner; Berlin: De Gruyter; open-access ed., Munich: Bayerische Akademie der Wissenschaften
4. ^ a b c d e f g Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
5. ^ a b c d e f g Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
6. ^ Isidore of Seville, Etymologiarum sive Originum libri XX, ed. W. M. Lindsay (Oxford, 1911).