Lewis & Short

rĭgo āvi, ātum, 1, v. a. [cf. Gr. βρέχω, to wet; Germ. Regen, rain].

  1. I. To wet, moisten, water, bedew any thing with a liquid (mostly poet. and in post-Aug. prose; cf.: irrigo, madefacio).
    1. A. Lit.: imbres omnia maria ac terras sparguntque rigantque, Lucr. 6, 612: Nilus rigat Aegyptum, id. 6, 714; Hor. C. 3, 3, 48 (for which, irrigat, Cic. N. D. 2, 52, 130); so, prata (fons), Lucr. 5, 602; Ov. F. 5, 210; cf.: lucum perenni aquā (fons). Liv. 1, 21: campos (Euphratis) accolae, Plin. 6, 27, 31, § 130: arbores, id. 17, 26, 40, § 249; cf. seminaria (opp. conspergere), Col. 5, 6, 8: quā Tanais Getas rigat, Tib. 4, 1, 146: lacrimis ora, Verg. A. 9, 251: fletibus ora, Ov. M. 11, 419; id. P. 2, 11, 9; id. A. A. 1, 532; Luc. 4, 180; Sen. Hippol. 990 al.
      Absol.: nubes nimbique rigantes, Lucr. 6, 521; so, accolae, Curt. 8, 9, 10.
      1. 2. Poet., transf.: natos vitali rore, i. e. to suckle, Cic. poët. Div. 1, 12, 20: solis uti lux ac vapor cernuntur terras rigare, bedew, flood, Lucr. 4, 203; cf. id. 5, 592: Babylonica, to wet (sc. with urine), id. 4, 1026.
    2. B. Trop., to water, bedew, etc.: omnium ingenia, Auct. Her. 4, 6, 9: ora alicujus Philetaeā aquā, Prop. 3 (4), 3, 52; Ov. Am. 3, 9, 26.
  2. II. Like irrigo, to lead, convey, or conduct water or any other liquid to a place (very rare).
    1. A. Lit.: aquam Albanam emissam per agros rigabis (= ad rigandum diduces), an old oracle in Liv. 5, 16 fin. Drak. N. cr.: vitalem sanguinem per venas, Plin. 11, 37, 69, § 182.
    2. B. Trop.: hinc motus per membra rigantur, are directed, conveyed, Lucr. 2, 262: somnum per pectora, Furius ap. Macr. S. 6, 1 (for which, irrigat, Lucr. 4, 908; Verg. A. 1, 692).