perlaceous,a.|pɜːˈleɪʃəs| [f.med.L. and Rom.perla pearl + -aceous.] Resembling pearl in appearance; pearly, nacreous. 1777Pennant Zool. (ed. 4) IV. 93 Anomia Ephippium,..color of inside perlaceous.1841Johnston in Proc.Berw.Nat. Club I. 264 Aperture white, perlaceous.