The substance that is acted upon by an enzyme or ferment.
2.
A surface on which an organism grows or is attached. Synonym:substratum.
3.
Any stratum or layer lying underneath another. Synonym:substratum.
4.
An indigenous language that contributes features to the language of an invading people who impose their language on the indigenous population. Synonym:substratum.
... exists at all, since in their books they cannot define it satisfactorily. Both mystics and rationalists, however, are deceived by their mental agility; the immediate exists, even if dialectic cannot explain it. What the rationalist calls nonentity is the substrate and locus of all ideas, having the obstinate reality of matter, the crushing irrationality of existence itself; and one who attempts to override it becomes to that extent an irrelevant rhapsodist, ... — The Life of Reason • George Santayana
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