lacunar

A ceiling constructed with recessed panels.

A recessed panel in such a ceiling.

One of the coffers or sunk compartments in ceilings or soffits formed of beams crossing one another, or resembling in structural form or for purposes of decoration such a construction of beams, as the stone ceilings of the Grecian Doric, those (generally formed of wood and plaster, and profusely decorated with gilding and ornament) common in Renaissance buildings, etc.

Hence A ceiling or soffit having lacunars.

Of or pertaining to a lacuna.