noun Geology.
  1. a bedded, blanketlike sedimentary deposit of organic origin built by marine organisms and including shell beds, flat reefs, and corals.

Origin of biostrome

1930–35; bio- + Greek strôma layer, bed; see stroma
Related formsbi·o·stro·mal, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for biostrome


  1. a rock layer consisting of a deposit of organic material, such as fossils

Word Origin for biostrome

C20: from bio- + Greek strōma covering
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