Stratum(redirected from Stratum spinosum)
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stratumsee SOCIAL STRATUM.
in geology, the principal form of occurrence of sedimentary rocks, reflecting their sequential deposition. A stratum has more or less homogeneous composition and is confined by two roughly parallel surfaces (the upper is the ceiling and the lower is the sole). The thickness of a stratum, from fractions of a meter to several meters, is much less than the length. Each stratum (with normal, undisturbed bedding) is younger than the one beneath it. Strata may also be composed of metamorphic rocks. Magmatic rocks and ores that are stratiform are called sheet deposits.
a designation for social levels or classes found in certain non-Marxist conceptions of social stratification.