Entry 1 sense Webster, 1913 Lucubratory · Lu·cu·bra·to·ry · IPA /ləˈkjubɹətɔɹi/ 01 a. Composed by candlelight, or by night; of or pertaining to night studies; laborious or painstaking. 1. Composed by candlelight, or by night; of or pertaining to night studies; laborious or painstaking.