aequilibrium

Forms

aequilībrium n (genitive aequilībriī or aequilībrī); second declension^[1]

Etymology

It is formed from Latin aequilībris (“evenly balanced, level”) + -ium;^[2][3] that adjective is made of aequus (“equal, level”) and lībra (“balance, pair of scales”).^[4][5] De Vaan traces lībra to Proto-Italic *leiþra- (“pound”).^[6]

Earliest recorded meaning

Seneca, in the Natural Questions, uses it of the level of water: some pieces of wood float almost wholly above it, some half submerged, and some sink down to the water's level.^[7][8][9]

Semantic evolution

Columella describes a vine that, as if held in balance on every side, rests on itself.^[2][7] Gellius used it figuratively for an exact equivalence in a discussion of the law of retaliation: whether a man whose limb was broken could break the other's limb in exactly equal measure.^[2][3] Solinus says Rome was called “square” because it was laid out ad aequilibrium.^[7]

Albertus Magnus used it figuratively for the balance of reason,^[10] and a 15th-century English word list glosses it as “a lewel”, a level.^[11] English took equilibrium around 1600, first for a balance of mind;^[4] Italian equilibrio also comes from it.^[12]

Timeline

• 4 BC–65 AD – Seneca uses it of the level of water.^[7][9]
• 1st century AD – Columella uses it of a vine balanced on every side.^[2][9]
• c. 165 AD – Gellius uses it for exact equivalence.^[2][9]
• first half of the 3rd century AD – Solinus uses it of the layout of Rome.^[7][9]
• c. 1600 – Borrowed into English as equilibrium.^[4]

Meanings

Noun

1. A state of equilibrium or equipoise; a level or horizontal position.^[2][8]
2. (figurative) Reciprocity, exact equivalence.^[2][8]
3. (Medieval Latin) A level (the instrument); a balance.^[11][10]

Related words

• aequilībrātus
• aequilībris
• aequilībritās
• aequus
• lībra
• English equilibrium

References

1. ^ a b c 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 Georges, Karl Ernst (1913–1918), Ausführliches lateinisch-deutsches Handwörterbuch, 8th ed., ed. Heinrich Georges, Hannover; Leipzig: Hahn
4. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ Victionarium (Latin Wiktionary), la.wiktionary.org
6. ^ de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
7. ^ a b c d e Thesaurus linguae Latinae (1900–), Leipzig: Teubner; Berlin: De Gruyter; open-access ed., Munich: Bayerische Akademie der Wissenschaften
8. ^ a b c Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
9. ^ a b c d e Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
10. ^ a b Mittellateinisches Wörterbuch bis zum ausgehenden 13. Jahrhundert (1967–), Munich: C. H. Beck; Bayerische Akademie der Wissenschaften
11. ^ 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
12. ^ Conte, Gian Biagio; Pianezzola, Emilio; Ranucci, Giuliano (2010), il Latino: Vocabolario della lingua latina, 3rd ed., Florence: Le Monnier