basis basis /ˈbeɪsɪs/

noun

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