noun
1.
something that supports or sustains anything immaterial
his argument rested on a basis of conjecture
Synonyms: base, bedrock, footing, foundation, ground, groundwork, infrastructure, root, substratum, underpinning; compare base 1
Related Word: axiom, fundamental, law, principle, theorem; assumption, postulate, premise, presumption, presupposition; essence, heart
2.
Synonyms: base 1, bed, bottom, footing, foundation, ground, groundwork, rest, seat, substructure
3.
something serving as a reason or justification for an action or opinion
resented such a challenge without basis or reason
Synonyms: foundation, warrant
Related Word: call, justification, right; ground(s), reason