noun (n)

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

  Example:
  He was President Lincoln's successor.
  

  Synonym:
  replacement
  

  source: wordnet30
• a thing or person that immediately replaces something or someone(noun.cognition)

  source: wordnet30
• a person who inherits some title or office(noun.person)

  Synonym:
  heir
  

  source: wordnet30
• One who succeeds or follows; one who takes the place which another has left, and sustains the like part or character; -- correlative to predecessor; as, the successor of a deceased king.(noun)

  source: webster1913