English Etymology From nacre + -ous. Pronunciation (UK, US) IPA(key): /ˈneɪ.kɹi.əs/ Audio (US):(file) Adjective nacreous (comparative more nacreous, superlative most nacreous) Of, or resembling nacre (mother of pearl). 2001, Neil Gaiman, chapter 11, in American Gods, Harper Collins, page 323:They are covered with a smooth, safe, nacreous layer to let them slip, pearllike, from our souls without real pain. Exhibiting lustrous or rainbow-like colors. Derived terms nacreous cloud See also opalescent, opaline, pearlescent Anagrams uncoarse, carneous, ur-oceans, Carusone, CrusoeanWikiwand - on Seamless Wikipedia browsing. On steroids.