noun (n)

• someone who mediates between speakers of different languages(noun.person)

  Synonym:
  translator
  

  source: wordnet30
• someone who uses art to represent something(noun.person)

  Example:
  His paintings reveal a sensitive interpreter of nature.
  She was famous as an interpreter of Shakespearean roles.
  

  source: wordnet30
• an advocate who represents someone else's policy or purpose(noun.person)

  Synonym:
  representative, spokesperson, voice
  

  source: wordnet30
• (computer science) a program that translates and executes source language statements one line at a time(noun.communication)

  Synonym:
  interpretive program
  

  source: wordnet30
• One who or that which interprets, explains, or expounds; a translator; especially, a person who translates orally between two parties.(noun)

  source: webster1913