to work, write, or study laboriously, esp. at night.
2.
to write learnedly.
Origin: 1615–25; < L lūcubrātus, ptp. of lūcubrāre to work by artificial light, equiv. to lūcu-, var. (before labials) of lūci-, comb. form of lūcēre to shine + -br(um) instrumental suffix + -ā- theme vowel + -tus ptp. suffix
[loo-kyoo-breyt] 
