noun (n)

• the act of furnishing an equivalent person or thing in the place of another(noun.act)

  Synonym:
  replacing
  

  source: wordnet30
• someone who takes the place of another person(noun.person)

  Synonym:
  alternate, surrogate
  

  source: wordnet30
• an event in which one thing is substituted for another(noun.event)

  Example:
  The replacement of lost blood by a transfusion of donor blood.
  

  Synonym:
  permutation, substitution, switch, transposition
  

  source: wordnet30
• a person or thing that takes or can take the place of another(noun.cognition)

  Synonym:
  substitute
  

  source: wordnet30
• filling again by supplying what has been used up(noun.process)

  Synonym:
  refilling, renewal, replenishment
  

  source: wordnet30
• a person who follows next in order(noun.person)

  Synonym:
  successor
  

  source: wordnet30
• The act of replacing.(noun)

  source: webster1913