basis

Synonyms: base bed bottom foot footing ground groundwork rest resting place seat substructure support

Synonyms: antecedent assumption authority axiom backbone background backing base bedrock cause center chief ingredient core crux data dictum essence essential evidence explanation footing fundamental hard fact heart infrastructure justification keynote keystone law nexus nucleus postulate premise presumption presupposition principal element principle proof reason root rudiment sanction security source substratum support theorem theory underpinning warrant