basis (nom)
Sens 1 : the main constituent, fundamental ingredient. [source : OED]
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Sens 2 : that by or on which anything immaterial is supported or sustained; a
foundation, support. [source : OED]
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Sens 3 : that on which anything is reared, constructed, or established, and by
which its constitution or operation is determined; groundwork, footing. [source : OED]