lucubrum

lūcŭbrum vocatum, quod luceat in umbra. Est enim modicus ignis, qui solet ex tenui stuppa ceraque formari, Isid. Orig. 20, 10, 8.

lucubrum [LL] Cf. lucubra. 1 a small lamp, cresset; b (defined as) ‘lighting of light’ (perh. concr., denoting single lamp or candle in candelabrum or sim.). a a luceo hoc ~um, -bri, i. modicum lumen, unde lucubro, -as i. vigilare Osb. Glouc. Deriv. 308; lucrubra Balsh. Ut. 53 v. l. (v. lucubra 1a); abbate ad matutinas in choro presente, ~um ostendetur priori, si obdormierit Obed. Abingd. 350; lugubrum, A. crusel Teaching Latin II 32; a cressett, batillus, crucibulum, lucrubrum CathA; a crosser, crucibulum, ~um Ib..  b ~um, leohtes leohting Ælf. Gl. 154. 16. 2 glimmer. ~um, a gnast or a glemerynge (Medulla) MED s. v. glimeringe; a glymerynge, lucubra, ~um CathA.

lūcŭbrum, ī, n. , petite lumière : Isid. Orig. 20, 10, 8.