Simple Definition of substratum
: a layer of something (such as soil or rock) that is under another layer
Full Definition of substratum
plural sub·stra·taplay \-tə\
Examples of substratum
drilled into the bedrock substratum
Origin of substratum
Medieval Latin, from Latin, neuter of substratus, past participle of substernere to spread under, from sub- + sternere to spread — more at strew
First Known Use: 1631
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Medical Dictionary: Definition of "substratum"
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