Lewis & Short

portus, ūs (gen. sing. porti, Turp. ap. Non. 491, 20: dat. plur. portibus, Liv. 27, 30, 7 et saep.; a better form than portubus), m. [por, whence porto, portitor].
Prop., an entrance; hence,

  1. I. A harbor, haven, port: Lunai portus, Enn. ap. Pers. 6, 9 (Ann. v. 16 Vahl.): portus Caietae, Cic. Imp. Pomp. 12, 33; id. Rep. 3, 31, 43; cf.: in Graeciae portus, id. ib. 1, 3, 5: e portu solvere, to sail out of port, id. Mur. 2, 4; so, e portu proficisci, Caes. B. G. 3, 14: ex portu exire, id. B. C. 2, 4: ex portu naves educere, id. ib. 1, 57; 2, 22: portum linquere, Verg. A. 3, 289: petere, to sail into, to enter, Cic. Planc. 39, 94; Verg. A. 1, 194: capere, Caes. B. G. 4, 36: occupare, Hor. Ep. 1, 6, 32: in portum venire, to enter the port, Cic. Sen. 19, 71; so, in portum ex alto invehi, id. Mur. 2, 4: in portum deferri, Auct. Her. 1, 11, 19: in portum pervenire, Caes. B. G. 4, 22: in portum se recipere, id. B. C. 2, 22: in portum navim cogere (al. conicere), Cic. Inv. 2, 32, 98: in portum penetrare, id. Verr. 2, 5, 37, § 96: portum tenere, to reach a port, id. Fam. 1, 9, 21: in portum voluntatis deduci, Vulg. Psa. 106, 30: in portu operam dare, to be an officer of the customs, Cic. Verr. 2, 2, 70, § 171; 2, 2, 72, § 176.
    With reference to the import-duty to be paid in ports: ex portu vectigal conservare, Cic. Imp. Pomp. 6, 15; id. Verr. 2, 2, 70, § 171.
    Prov.: in portu navigare, i. e. to be in safety, out of all danger, Ter. And. 3, 1, 22; so, in portu esse, Cic. Fam. 9, 6, 4.
      1. 2. Poet., transf., the mouth of a river, where it empties into the sea, Ov. H. 14, 107; id. Am. 2, 13, 10.
    1. B. Trop., as also the Greek λιμήν, and our haven, a place of refuge, an asylum, retreat (class.; a favorite trope of Cicero): portus corporis, Enn. ap. Cic. Tusc. 1, 44, 107 (Trag. v. 415 Vahl.): tamquam portum aliquem exspecto illam solitudinem, Cic. de Or. 1, 60, 255; so with tamquam, id. Brut. 2, 8: se in philosophiae portum conferre, id. Fam. 7, 30, 2: regum, populorum, nationum portus erat et refugium senatus, id. Off. 2, 8, 26: exsilium non supplicium est, sed perfugium portusque supplicii, id. Caecin. 34, 100; id. Tusc. 1, 49, 118: hic portus, haec arx, haec ara sociorum, id. Verr. 2, 5, 48, § 126; so, nam mihi parta quies, omnisque in limine portus, i. e. security is at hand, Verg. A. 7, 598: venias portus et ara tuis, Ov. H. 1, 110: vos eritis nostrae portus et ara fugae, id. P. 2, 8, 68.
  2. II. In the oldest Latinity, a house (as a place which one enters): portum in XII. pro domo positum omnes fere consentiunt, Fest. p. 233 Müll.
  3. * III. A warehouse: portus appellatus est conclusus locus, quo importantur merces et inde exportantur, Dig. 50, 16, 59: Licini, Cassiod. Var. 1, 25.