[ba.sis] n, pl ba.ses [L--more at base] (14c) 1: the bottom of something considered as its foundation
2: the principal component of something 3 a: something on which something else is established or based b: an underlying condition or state of affairs "hired on a trial ~" "on a first-name ~"
4: the basic principle
5: a set of linearly independent vectors in a vector space such that any vector in the vector space can be expressed as a linear combination of them with appropriately chosen coefficients