Lewis & Short

calcŭlus, i, m. dim. [2. calx; cf. Paul. ex Fest. p. 46].

  1. I. In gen., a small stone, a pebble: conjectis in os calculis, Cic. de Or. 1, 61, 261: Demosthenes calculos linguā volvens dicere domi solebat, Quint. 11, 3, 54; Vitr. 7, 2: argilla et dumosis calculus arvis, gravel in the thorny fields, Serv. ad Verg. G. 2, 180; Plin. 4, 8, 15, § 37; 28, 9, 33, § 124.
    1. B. Trop., of discourse: qui tenui venulā per calculos fluunt, Quint. 12, 10, 25.
  2. II. Esp.
    1. A. A stone in the bladder or kidneys, the gravel, stone, Cels. 7, 26: curare, Plin. 20, 21, 86, § 234: comminuere et eicere, id. 20, 4, 13, § 23; cf. eicere, Suet. Aug. 80: movere, Plin. 20, 22, 91, § 248: exturbare, id. 20, 10, 42, § 109: frangere, id. 22, 21, 29, § 59: rumpere, id. 23, 8, 80, § 153.
    2. B. A draughtsman, a stone or counter used in playing draughts. called duodecim scripta, in which, as in chess, by driving a piece from one square to another, the person beaten could not finally move at all (ad incitas redactus est): in lusu duodecim scriptorum cum prior calculum promovisset, etc., Quint. 11, 2, 38; cf. Ov. A. A. 2, 207; 3, 357; id. Tr. 2, 478; Plin. Ep. 7, 24, 5; Mart. 14, 20; Isid. Orig. 18, 67: calculorum ludus, Cael. Aur. Tard. 1, 5, 165.
      1. 2. Trop.: calculum reducere, to take back a move: tibi concedo, quod in XII. scriptis solemus, ut calculum reducas, si te alicujus dati paenitet, Cic. ap. Non. p. 170, 28 (Hortens. Fragm. 51 B. and K.): quā re nunc saltem ad illos calculos revertamur, quos tum abjecimus, i. e. those principles of action, id. Att. 8, 12, 5.
    3. C. A stone used in reckoning on the counting-board; hence meton., a reckoning, computing, calculating: calculi et rationes, Quint. 11, 3, 59; 7, 4, 35; 8, 3, 14; 12, 11, 18 Spald.: calculos subducere, to compute, reckon, cast up, Cic. Fin. 2, 19, 60: ponere, Col. 3, 3, 7: ponere cum aliquo, Plin. Pan. 20, 5: de posteris cogitanti in condicionibus deligendus ponendus est calculus, id. ib. 1, 14, 9: amicitiam ad calculos vocare, to subject to an accurate reckoning, hold to a strict account, Cic. Lael. 16, 58: si ad calculos eum respublica vocet, settles accounts, reckons, Liv. 5, 4, 7: revocare aliquid ad calculos, Val. Max. 4, 7, 1: ratio calculorum, Col. 1, 3, 8.
      1. 2. Trop.: cum aliquā re parem calculum ponere, i.e. to render equal for equal, Plin. Ep. 5, 2, 1: quos ego movi calculos, considerations which I have suggested, id. ib. 2, 19, 9.
    4. D. In the most ancient per., a stone used in voting; a vote, sentence, decision, suffrage; a white one for assent or acquittal, a black for denial or condemnation; cf. Ov. M. 15, 41 sq.; App. M. 10, p. 242.
      Hence judicialis, Imp. Just. Cod. 3, 1, 12: deteriorem reportare, i. e. an adverse decision, Impp. Diocl. et Max. Cod. 7, 62, 10: calculis omnibus, by a unanimous vote, App. M. 7, p. 191, 21.
      Trop.: si modo tu fortasse errori nostro album calculum adjeceris, i. e. approve, Plin. Ep. 1, 2, 5.
    5. E. The Thracians were accustomed to preserve the recollection of fortunate occurrences by white stones, and of unfortunate by black, Plin. 7, 40, 41, § 131.
      Hence,
      1. 2. Trop.: o diem laetum, notandumque mihi candidissimo calculo! i. e. a most happy day! Plin. Ep. 6, 11, 3; cf. Mart. 12, 34, 9, § 53; Pers. 2, 1 sq.
  3. F. In late Lat., a small weight: calculus constat ex granis ciceris duobus, Auct. Ponder ap. Goes. Agr. p. 322 (in Isid. Orig. 16, 25, 8, called calcus).