per·​lite ˈpər-ˌlīt How to pronounce perlite (audio)
: 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
perlitic adjective

Example Sentences

Recent Examples on the Web For pots, use cactus soil with the addition of about 30% to 40% perlite to increase drainage, allowing water to drain through. Nicole Sours Larson, San Diego Union-Tribune, 22 Aug. 2022 According to Petal Republic, the best combination is a 2:2:1 blend of cactus potting mix, coarse sand and perlite or pumice. Alyssa Gautieri, Good Housekeeping, 5 Aug. 2022 This mix contains some peat moss along with perlite, worm castings, and lime. Brittany Vanderbill, Better Homes & Gardens, 6 May 2022 One local collector recommends a mix that is half seed starter mix, one-quarter coir chunks or chunky orchid bark, and a quarter small lava or pumice, or large perlite. Nan Sterman, San Diego Union-Tribune, 5 Mar. 2022 Inorganic amendments are perlite, pumice, vermiculite and Utelite. oregonlive, 2 Jan. 2022 The sundews should be grown in a medium of four parts fertilizer-free peat moss to one part perlite. New York Times, 26 Nov. 2021 Pumice or perlite — Quarried lava rock increases drainage and space for roots to grow. Claire Reid, Los Angeles Times, 10 Aug. 2021 They are made from Portland cement, perlite (or vermiculite) and water. Linda Gandee, cleveland, 6 Sep. 2021 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'perlite.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


French, from perle pearl

First Known Use

1833, in the meaning defined above

Time Traveler
The first known use of perlite was in 1833

Dictionary Entries Near perlite

Cite this Entry

“Perlite.” Dictionary, Merriam-Webster, Accessed 27 Nov. 2022.

Kids Definition



per·​lite ˈpər-ˌlīt How to pronounce perlite (audio)
: a glassy mineral of volcanic origin that when expanded by heat forms a lightweight material capable of absorbing liquids (as water)

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