Lewis & Short

fulgur (also in the nom. FVLGVS, acc. to Fest. s. v. fulgere, p. 92 fin. Müll. N. cr.), ŭris, n. [fulgeo], flashing lightning, lightning.

  1. I. Prop. (= splendor fulminis, opp. fulmen, a thunderbolt): fulgur, ignis qui coruscat fulmine, Non. 5, 33: eodem modo fit fulgur, quod tantum splendet, et fulmen, quod incendit … fulmen est fulgur intentum, Sen. Q. N. 2, 57, 3: nimbi immixtaque fulgura ventis, Ov. M. 3, 300: credas et rapidum Aetnaeo fulgur ab igne jaci, id. F. 1, 574: passim fremitus et fulgura fiunt, Lucr. 6, 270: CAELI FVLGVRA REGIONIBVS RATIS TEMPERANTO, Cic. Leg. 2, 8, 21: de fulgurum vi dubitare, id. Div. 1, 10, 16; cf.: fulgura interpretantes, id. ib. 1, 6, 12; cf. also: consultus de fulgure haruspex, Suet. Dom. 16; Tac. A. 15, 47 al.: tonitrua et fulgura paulo infirmius expavescebat, Suet. Aug. 90; cf. id. Calig. 51: qui ad omnia fulgura pallent, Juv. 13, 223: tonitruque et fulgure terruit orbem, Ov. M. 14, 817: dium fulgur appellabant diurnum, quod putabant Jovis, ut nocturnum Summani, Fest. p. 75 Müll.; cf.: provorsum fulgur appellatur, quod ignoratur noctu an interdiu sit factum, Fest. p. 229 Müll. N. cr.
  2. II. Transf.
    1. A. For fulmen, a lightning-flash that descends and strikes, a thunder-bolt (not in class. prose): feriunt summos fulgura montes, Hor. C. 2, 10, 12; Lucr. 6, 391: caelo ceciderunt plura sereno fulgura, Verg. G. 1, 488.
      1. 2. In partic., in relig. lang.: condere fulgur, to bury a thing struck by lightning: aliquis senior, qui publica fulgura condit, Juv. 6, 586: ‡ fulgur conditum, Inscr. Orell. 2482; cf. Luc. 1, 606.
    2. B. For fulgor, brightness, splendor (poet. and very rare): solis, Lucr. 2, 164; so, flammaï, id. 1, 725; cf.: nictantia flammae, id. 6, 182: clarae coruscis Fulguribus tedae, id. 5, 297: galeae, Claud. Cons. Hon. 3, 31.