something that underlies, supports, or is essential to something else, esp an abstract idea
a principle on which something depends or from which something has issued
maths(of a vector space) a maximal set of linearly independent vectors, in terms of which all the elements of the space are uniquely expressible, and the number of which is the dimension of the spacethe vectors x, y and z form a basis of the 3-dimensional space all members of which can be written as a x + b y + c z
Word Origin for basis
C14: via Latin from Greek: step, from bainein to step, go
1570s, "bottom or foundation (of something material)," from Latin basis "foundation," from Greek basis "a step, stand, base, that whereon one stands," from bainein "go, step" (see come). Transferred and figurative senses (of immaterial things) are from c.1600.