grounds in WordNet English dictionary

1. a justification for something existing or happening
   "he had no cause to complain"; "they had good reason to rejoice"
   cause  reason  grounds 
   
2. the enclosed land around a house or other building
   "it was a small house with almost no yard"
   yard  grounds  curtilage 
   
3. your basis for belief or disbelief; knowledge on which to base belief
   "the evidence that smoking causes lung cancer is very compelling"
   evidence  grounds 
   
4. a tract of land cleared for some special purposes (recreation or burial etc.)
   grounds 
   
5. dregs consisting of solid particles (especially of coffee) that form a residue
   "it is a Middle Eastern custom to read your future in your coffee grounds"
   grounds 
   

grounds in English Wiktionary