Definition of "opaline" in English

adjective

1. Resembling opal in having a milky white iridescence.

noun

1. A clear to white liquid secreted by sea hares (genus Aplysia) that becomes viscous upon contact with water.

   • The attack on a sea hare by a spiny lobster causes release of the whitish opaline, followed the co-release of both opaline and ink.

2. (mineralogy) Any of several minerals resembling opal, including a variety of yellow chalcedony.

3. Synonym of opal glass.