noun (n)

• the leading units moving at the head of an army(noun.group)

  Synonym:
  van
  

  source: wordnet30
• any creative group active in the innovation and application of new concepts and techniques in a given field (especially in the arts)(noun.group)

  Synonym:
  avant-garde, new wave, van
  

  source: wordnet30
• the position of greatest importance or advancement; the leading position in any movement or field(noun.cognition)

  Synonym:
  cutting edge, forefront
  

  source: wordnet30
• The troops who march in front of an army; the advance guard; the van.(noun)

  source: webster1913