- Geol. a greenish volcanic glass, similar to obsidian, with a pearly luster and multiple, minute concentric cracks, used as insulation and in making concrete, plaster, etc.
Origin: Fr from perle, pearl
- perlitic adjective
Used by arrangement with John Wiley & Sons, Inc.
Origin: French (from perle, pearl, from Old French; see pearl1) or German Perlite (from Perle, pearl, ultimately from Vulgar Latin *pernula).
- per·litˈic adjective