The Collaborative International Dictionary
Pisolite \Pi"so*lite\, n. [Gr. ? a pea + -lite: cf. F. pisolithe.] (Min.) A variety of calcite, or calcium carbonate, consisting of aggregated globular concretions about the size of a pea; -- called also peastone, peagrit.
Note: O["o]lite is similar in structure, but the concretions are as small as the roe of a fish.
Wiktionary
n. (context geology English) A sedimentary rock formed from pisoliths
Wikipedia
A pisolite is a sedimentary rock made of pisoids, which are concretionary grains – often of calcium carbonate, but sometimes of rarer minerals – which resemble ooids but are always more than 2 mm in diameter. These grains are approximately spherical and have concentric layers reaching 10 mm in diameter.
The name derives from the Hellenic word for pea. Bauxites, limonites and siderites often have a pisolitic structure.