Lewis & Short

cŏlumna, ae, f. [root cel- of excello; v. columen, of which it is orig. a collat. form].

    1. A. A projecting object, a column, pillar, post (very freq.), Vitr. 4, 1, 1 sq.; 3, 3; Varr. R. R. 3, 5, 11: columnae et templa et porticus sustinent, tamen habent non plus utilitatis quam dignitatis, Cic. de Or. 3, 46, 180; id. Verr. 2, 1, 51, §§ 133 and 134; Quint. 5, 13, 40: columnae Doricae, Ionicae, Tuscanicae, Corinthiae, Atticae, Plin. 36, 22, 56, § 178 sq.; Vitr. 4, 1, 1 sqq.: Rostrata, a column ornamented with beaks of ships, erected in honor of Duellius, the conqueror of the Carthaginians, Quint. 1, 7, 12 Spald.; fragments of the inscription on it are yet extant, v. in the Appendix: Maenia, also absol. Columna, a pillory in the Forum Romanum, where thieves, criminal slaves, and debtors were judged and punished, Cic. Div. in Caecil. 16, 50 Ascon.
      Absol.: ad columnam pervenire. Cic. Clu. 13, 39: adhaerescere ad columnam, id. Sest. 8, 18; cf. Dict. of Antiq. s. v. columna.
      Plur.: columnae, as the sign of a bookseller’s shop, Hor. A. P 373 Orell. ad loc.
      From the use of pillars to designate boundaries of countries: Columnae Protei = fines Aegypti, Verg. A. 11, 262; and: Columnae Herculis, i. e. Calpe et Abyla, Mel. 1, 5, 3; 2, 6, 8; Plin. 3, prooem. § 4; Tac. G. 34.
      Prov.: incurrere amentem in columnas, Cic. Or. 67, 224.
      1. * 2. Trop., a pillar, support; of Augustus, Hor. C. 1, 35, 14.
      2. 3. Transf., of objects resembling a pillar; so,
        1. a. Of the arm (comice): ecce autem aedificat: columnam mento suffigit suo, Plaut. Mil. 2, 2, 54.
        2. b. A water-spout, Lucr. 6, 426; 6, 433; Plin. 2, 49, 50, § 134.
        3. c. Of fire, a meteor, Sen. Q. N. 7, 20, 2; cf. of the pillar of cloud and of fire which guided the Exodus, Vulg. Exod. 13, 21 sq.
        4. d. Membrum virile, Mart. 6, 49; 11, 51; Auct. Priap. 9, 8.
        5. e. Narium recta pars eo quod aequaliter sit in longitudine et rotunditate porrecta, columna vocatur, Isid. Orig. 11, 1, 48.
    2. * B. The top, summit; so only once of the dome of heaven, Cic. poët. Div. 1, 12, 21; cf. columen.