lacunar

/L AA0 K UW1 N ER0/
noun
  1. 1

    A sunken panel or coffer in a ceiling or a soffit.

  2. 2

    A ceiling containing panels of this kind.

adjective
  1. 1

    Of or pertaining to a lacuna

Synonyms

Source: https://en.wiktionary.org/wiki/lacunar