Definition of biostrome in US English:

biostrome

noun

Geology
  • A deposit consisting of a bed or sheet (as opposed to a mound or domed structure) of the calcareous skeletal remains of sedentary organisms (shells, crinoids, corals, etc.).

Origin

1930s. From bio- + ancient Greek στρῶμα mattress, bed: compare quot. 1932.

Pronunciation

biostrome

/ˈbʌɪəstrəʊm/