basis in WordNet English dictionary

1. 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  foundation  fundament  groundwork  cornerstone 
   
2. the most important or necessary part of something
   "the basis of this drink is orange juice"
   basis  base 
   
3. a relation that provides the foundation for something
   "they were on a friendly footing"; "he worked on an interim basis"
   footing  basis  ground