I. A small reckoning, a little account: “subduxi ratiunculam, Quantum aeris mihi sit, quantumque alieni siet,” Plaut. Curc. 3, 1; id. Capt. 1, 2, 89; Ter. Phorm. 1, 1, 2.—
II. A slight ground or reason: “leves,” Cic. Tusc. 4, 19, 43: “huic incredibili sententiae ratiunculas suggerit,” id. N. D. 3, 29, 73.—
2. In dialectics, a petty syllogism: “concludunt ratiunculas Stoici,” Cic. Tusc. 2, 12, 29: humanis ratiunculis falsis contravenire conantur, Aug. Civ. Dei, 20, 1, 1.