Lewis & Short

ŏnus (in good MSS. also wr. hŏnus), ĕris, n. [etym. dub.; cf. Sanscr. anas, a wagon for freight], a load, burden (cf. pondus).

  1. I. Lit.
    1. A. In gen.: oneris maximi pondus, Vitr. 10, 8: onus sustinere, Plaut. As. 3, 3, 68: cum gravius dorso subiit onus (asellus), Hor S. 1, 9, 20: tanti oneris turris, Caes. B. G. 2, 30: ad minimum redigi onus, Ov M. 14, 149.
    2. B. In partic.
      1. 1. Of goods, baggage, etc., a load, lading, freight, cargo: insula Delos, quo omnes undique cum mercibus atque oneribus commeabant, Cic. Imp. Pomp. 18, 55: onera afferuntur, Plin. 6, 23, 26, § 104: (naves) ad onera et ad multitudinem jumentorum transportandam paulo latiores, Caes. B. G. 5, 1, 2: jumentis onera deponere, loads, packs, id. B. C. 1, 80.
      2. 2. Poet., the burden of the womb, the fœtus, embryo: gravidi ventris, Ov. Am. 2, 13, 1; id. F. 2, 452; id. H. 4, 58; Phaedr. 1, 18, 5.
      3. 3. The excrements: ciborum onera reddere, Plin. 8, 27, 41, § 97: duri ventris solvere, Mart. 13, 29, 2.
  2. II. Trop
    1. A. A burden, in respect of property, i. e. a tax or an expense (usually in the plur.): municipium maximis oneribus pressum, Cic. Fam. 13, 7, 2: haec onera in dites a pauperibus inclinata, Liv. 1, 43: patria, Suet. Calig. 42: haerere in explicandis oneribus, id. Dom. 12 init.: oneribus novis turbantur provinciae, Tac. A. 4, 6.
    2. B. A load, burden, weight, charge, trouble, difficulty of any kind (so most freq. in Cic.; cf. molestia): magni sunt oneris; quicquid imponas, vehunt, capable of bearing great burdens, Plaut. Most. 3, 2, 95: quae (senectus) plerisque senibus sic odiosa est, ut onus se Aetnā gravius dicant sustinere, Cic. Sen. 2, 4: onus atque munus magnum, id. de Or. 1, 25, 116: hoc onus si vos adlevabitis, id. Rosc. Am. 4, 10: officii, id. ib.: probandi, the burden of proof, obligation to prove, Dig. 31, 1, 22; Cic. Rep. 1, 23, 37: oneri esse, to be a burden, Liv. 23, 43; Vulg. 2 Reg. 15, 33: neque eram nescius, quantis oneribus premerere susceptarum rerum, Cic. Fam. 5, 12, 2: epici carminis onera lyrā sustinere, Quint. 10, 1, 62.
    3. C. (Eccl. Lat.) The burden of a prophecy, the woes predicted against any one: Babylonis, Vulg. Isa. 13, 1: Tyri, id. ib. 23, 1.
      With subj.gen.: Domini, Vulg. Jer. 23, 33: verbi Domini, id. Zach. 12, 1.