Lewis & Short

ordĭor, orsus, 4 (fut. ordibor for ordiar: non parvam rem ordibor, Att. ap. Non. 39, 22; part. perf. orditus, Sid. Ep. 2, 9; Vulg. Isa. 25, 7), v. dep., lit., to begin a web, to lay the warp; hence, also, in gen., to begin, undertake a thing: ordiri est rei principium facere, unde et togae vocantur exordiae, Fest. p. 185 Müll.; cf. Isid. 19, 29, 7: telam, Hier. in Isa. 9, 30, v. 1; Vulg. Isa. 25, 7.

  1. I. Lit., to begin to weave a web, to weave, spin: araneus orditur telas, Plin. 11, 24, 28, § 80.
    So of the Fates: Lachesis plenā orditur manu, Sen. Apoc. 4: (Parca) hominis vitam orditur, Lact. 2, 10, 20.
  2. II. In gen., to begin, commence, set about, undertake (class.; syn.: incipio, incoho, infit); constr. with acc., de, inf., or absol.
          1. (α) With acc.: reliquas res, Cic. Fam. 5, 12, 2: alterius vitae quoddam initium ordimur, id. Att. 4, 1: reliquos, to relate, describe, Nep. Alc. 11, 6: querelae ab initio tantae ordiendae rei absint. Liv. praef. § 12: majorem orsa furorem, Verg. A. 7, 386.
          2. (β) With de: paulo altius de re ordiri, Cic. Verr. 2, 4, 47, § 105.
          3. (γ) With inf.: ea, de quā disputare ordimur, Cic. Brut. 6, 22: cum adulescens orsus esset in foro dicere, id. ib. 88, 301: cum sic orsa loqui vates, Verg. A. 6, 125: et orsa est Dicere Leuconoë, Ov. M. 4, 167: tunc sic orsa loqui, id. ib. 4, 320.
          4. (δ) Absol., to begin, commence, set out, take or have a beginning: unde est orsa, in eodem terminetur oratio, Cic. Marcell. 11, 33: Veneris contra sic filius orsus, thus began (to speak), Verg. A. 1, 325: sic Juppiter orsus, id. ib. 12, 806; so commonly with specification of the point from which: unde ordiri rectius possumus quam a naturā? Cic. Tusc. 5, 13, 37 init.: a principio, id. Phil. 2, 18, 44: a facillimis, id. Fin. 1, 5, 13: a capite, Plin. 25, 11, 83, § 132.
            (ε) Of things or subjects, to begin, to be begun (where the verb may be taken in pass. sense): tormina ab atrā bile orsa mortifera sunt, Cels. 2, 8: cum ex depressiore loco fuerint orsa fundamenta, Col. 1, 5, 9: sed ab initio est ordiendus (Themistocles), i. e. I must begin (his life) at the beginning, Nep. Them. 1, 2; cf.: ab eo nobis causa ordienda est, Cic. Leg. 1, 7, 21.