Lewis & Short

bes, bessis, m. (nom. bessis, Paul. ex Fest. p. 33 Müll.; Prisc. Ponder. p. 1348 P.) [be-is = binae partes assis].

  1. I. Two thirds of a unit (the as); eight unciae, or twelfths (cf. as): bessis octo sunt unciae (8/12 = 2/3), triens quattuor, Paul. ex Fest. l. l.
    1. A. As a coin: fenus ex triente Idib. Quint. factum erat bessibus, i. e. instead of the previous monthly interest of 1/3 %, 2/3 % was now reckoned; thus, acc. to the present mode of calculating, for the year, the interest advanced from 4 % (12X1/3) to 8 % (12X2/3), * Cic. Att. 4, 15, 7.
    2. B. In gen., two thirds of any whole.
      1. 1. Of shares in a partnership: Nerva constituit, ut tu ex triente socius esses, ego ex besse, Dig. 17, 2, 76.
      2. 2. Of a sum of money: exsolvere bessem pretii, Dig. 17, 1, 12.
      3. 3. Of a tract of land: emere bessem fundi, Dig. 16, 21, 2, § 39: bisque novem, Nemeaee, dabis, bessemque (i. e. eight months) sub illis, Manil. 3, 367.
      4. 4. Of a jugerum: partes duae tertiae pedes decem novem milia et ducentos, hoc est bes, in quo sunt scripula CXCII., Col. 5, 1, 11.
      5. 5. Of a measure of capacity: bes sextarii, Scrib. Comp. 126.
      6. 6. Of a pound, = 8 ounces: in binos semodios farinae satis esse bessem fermenti, Plin. 18, 11, 26, § 102; Scrib. Comp. 157.
      7. 7. Of an inheritance: heres ex besse, Plin. Ep. 7, 24, 2.
    3. C. Meton. for eight: quincunces et sex cyathos bessemque bibamus, Caïus ut fiat Julius et Proculus (i. e. so many letters were comprised in these names; cf. 1. bibo, 2. e.), Mart. 11, 36, 7 and 8.
    4. D. Bes alter = (12+8)/12 = 1 2/3, Fest. s. v. triens, p. 363 Müll.
  2. II. In mathematics, where the cardinal number is six (cf. as
    Note:), bes = 4, Gr. δίμοιρος, Vitr. 3, 1, p. 61 Rod. and bes alter = (6+4)/6 = 1 2/3, Gr. ἐπιδίμοιρος, id. ib.