Definition of perlite
: volcanic glass that has a concentric structure, appears as if composed of concretions, is usually grayish and sometimes spherulitic, and when heated expands to form a lightweight aggregate used especially in concrete and plaster and as a medium for potting plants
perliticplay \ˌpər-ˈli-tik\ adjective
Origin and Etymology of perlite
French, from perle pearl
First Known Use: 1833
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