Entry 4 senses · 2 variants Webster, 1913 Opaline /ōp'-əl-ēnˌ/ · O·pal·ine · IPA /ˈoʊpəlˌiːn/ a. n. 01 a. Of, pertaining to, or like, opal in appearance; having changeable colors like those of the opal. 1. Of, pertaining to, or like, opal in appearance; having changeable colors like those of the opal. 02 n. An opaline variety of yellow chalcedony. 1. An opaline variety of yellow chalcedony. 2. Opal glass. 3. An opaline color or expanse.