groundwork in WordNet English dictionary

1. lowest support of a structure
   "it was built on a base of solid rock"; "he stood at the foot of the tower"
   foundation  base  fundament  foot  groundwork  substructure  understructure 
   
2. 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 
   
3. preliminary preparation as a basis or foundation
   "we are prepared today because of groundwork that was done ten years ago"
   groundwork