I.gen. plur. lacunariorum for lacunarium, Vitr. 4, 3, 1 al.; dat. plur. lacunariis, id. 5, 2), n. lacuna, a wainscoted and gilded ceiling of an unvaulted chamber, a panel-ceiling, a ceiling (so called from its sunken spaces; “class.),” Vitr. 7, 2: “non ebur neque aureum Mea renidet in domo lacunar,” Hor. C. 2, 18, 2: “gladium e lacunari seta equina aptum demitti jussit,” Cic. Tusc. 5, 21, 62: primus lacunaria pingere instituit (Polygnotus), Plin. 35, 11, 40, § 124.—Prov.: “spectare lacunar,” to gaze at the ceiling, to be wilfully blind, Juv. 1, 56.—
II. Plur.: lăcūnārĭa , ōrum (-arium, App. Flor. 18, p. 83), n., panels of the under surface of a cornice, Vitr. 4, 3, 1; 7, 2, 2; 5, 2, 1; Plin. 35, 11, 40, § 124.