binus

From Proto-Italic *dwiznos, equivalent to bis (“twice”) +‎ -nus (distributive numeral-forming suffix).

• (Classical Latin) IPA^(key): /ˈbiː.nus/,
• (modern Italianate Ecclesiastical) IPA^(key): /ˈbi.nus/,

bīnus (feminine bīna, neuter bīnum); first/second-declension numeral

1. (in the plural) two each
   • 27 BCE – 25 BCE, Titus Livius, Ab Urbe Condita 26.1:

     Et praetoribus prioris anni M. Iunio in Etruria, P. Sempronio in Gallia cum binis legionibus quas habuerant prorogatum est imperium.

     And the military command of Marcus Junius in Etruria and Publius Sempronius in Gaul, praetors of the previous year, was extended with the two legions which they had each held.

2. (chiefly plural) in pairs
   • 29 BCE – 19 BCE, Virgil, Aeneid I.311–312:

     ipse uno graditur comitatus Achate,
     Bina manu lato crispans hastilia ferro.

     Achates folowing him, Aeneas leaves away his men,
     Clasping with his hand to his two broad-tipped javelins.

3. occurring twice, twofold, double, binary

Cicero notes that bīnī was phonetically similar to the obscene Ancient Greek word βῑνεῖ (bīneî, “fucks”, 3rd person singular present active indicative).^[1]

This is part of the Latin series of distributive numerals. These numerals are inflected as first/second-declension adjectives; in Classical Latin, they typically accompany plural nouns (with which they agree in case and gender) and have the following functions:

• to express the sense “ s each/apiece”, as in hominis digiti ternos articulos habent, “a man’s fingers have three joints each” (Pliny the Elder, Natural History 11.244.3).

• to express multiplication after a numeral adverb,^[2] as in Gallinaciis enim pullis bis deni dies opus sunt, pavoninis ter noveni "hens' need twice ten days, peahens' thrice nine" (Marcus Terentius Varro, Res Rusticae 3.9.10)

• to express the sense of cardinal numerals when used with pluralia tantum (plural-only nouns) such as castra "camp":^[2] for example, "twelve camps" is expressed by duodēna castra (Pliny the Elder, Natural History 7.105.5). Distributive forms are regularly used in this context for the number 2 and for all numbers greater than 4. For 1, plural-only nouns are used with plural inflected forms of the cardinal ūnus (“one”), as in ūnae scālae "one flight of stairs" (rather than with forms of the distributive numeral singulus). For 3 and 4, plural-only nouns are used with the plural inflected forms of trīnus^[3] and quadrīnus, as in trīna castra "three camps" (rather than with forms of ternus and quaternus, which tend to be used in distributive function^[4]).

These adjectives do not normally occur in the singular.^[5] Because of this, many grammars and dictionaries treat them as plural-only words and refer to them using the nominative masculine plural form in -ī, rather than the nominative masculine singular form in -us (which is often unattested in Classical Latin). However, some of these adjectives are attested in the singular in Classical Latin poetry^[2] (e.g. Sed neque Centauri fuerunt, nec tempore in ullo / esse queunt duplici natura et corpore bino..., Titus Lucretius Carus, De Rerum Natura 5.879, and Sic tu bis fueris consul, bis consul et ille, / inque domo binus conspicietur honor, Publius Ovidius Naso, Epistulae ex Ponto 4.9.64; "corpore bino" here seems to have the sense of "twofold body", and "binus ... honor" the sense of "double/dual/twofold honor"). Singular forms are also attested in postclassical Latin, where these adjectives sometimes have non-distributive meanings (taking an ordinal, cardinal, or collective sense instead). These alternative senses are sometimes continued by Romance descendants (e.g. Spanish noveno (“ninth”) from Latin novēnus).

The genitive plural of singulus is usually singulōrum/singulārum, but distributive numerals greater than one commonly use short genitive plural forms ending in -um rather than the longer forms ending in -ōrum and -ārum.^[5][3]

First/second-declension adjective (distributive, normally plural-only; short genitive plurals in -num preferred).

• bīnārius
• binō (Medieval Latin)
• combīnō

• “binus”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• binus in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
• Carl Meißner, Henry William Auden (1894) Latin Phrase-Book‎, London: Macmillan and Co.
  • (ambiguous) to be absolutely ignorant of arithmetic: bis bina quot sint non didicisse
    
  • (ambiguous) to lend at 24 per cent.[TR1: binis centesimis fenerari
    
• “binary”, in The Century Dictionary , New York, N.Y.: The Century Co., 1911, →OCLC.