noun (n)

• the act of producing offspring or multiplying by such production(noun.act)

  Synonym:
  generation, propagation
  

  source: wordnet30
• a multiplicative increase(noun.process)

  Example:
  Repeated copying leads to a multiplication of errors.
  This multiplication of cells is a natural correlate of growth.
  

  source: wordnet30
• an arithmetic operation that is the inverse of division; the product of two numbers is computed(noun.act)

  Example:
  The multiplication of four by three gives twelve.
  

  Synonym:
  times
  

  source: wordnet30
• The act or process of multiplying, or of increasing in number; the state of being multiplied; as, the multiplication of the human species by natural generation.(noun)

  source: webster1913