Main entry: foundation, fundament, groundwork, cornerstone, base, basis
Definition: the fundamental assumptions from which something is begun or developed or calculated or explained
Usage: the whole argument rested on a basis of conjecture
Main entry: footing, ground, basis
Definition: a relation that provides the foundation for something
Usage: they were on a friendly footing; he worked on an interim basis
Definition: the most important or necessary part of something
Usage: the basis of this drink is orange juice