noun (n)

• education or instruction in the fundamentals of a field of knowledge(noun.cognition)

  Example:
  A good grounding in mathematics.
  

  Synonym:
  foundation
  

  source: wordnet30
• fastening electrical equipment to earth(noun.act)

  Synonym:
  earthing
  

  source: wordnet30
• The act, method, or process of laying a groundwork or foundation; hence, elementary instruction; the act or process of applying a ground, as of color, to wall paper, cotton cloth, etc.; a basis.(noun)

  source: webster1913