substratum

sub·stra·tum

(sŭb-strā'tŭm),

Any layer or stratum lying beneath another.

[L. see substrate]

substratum

(sŭb′strā′təm, -străt′əm)

n. pl. sub·strata (-strā′tə, -străt′ə) or sub·stratums

Biology A substrate.

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sub·stra′tive adj.

substrate

, substratum (sub'strat) (sub-stra'tum) [L. substratum, to lie under]

1. An underlying layer or foundation.

2. A base, as of a pigment.

3. The substance acted upon, as by an enzyme. See: enzyme