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