noun (n)

• the quality of being in front or (in lower animals) toward the head(noun.attribute)

  Antonym:
  posteriority
  

  source: wordnet30
• preceding in time(noun.attribute)

  Synonym:
  antecedence, antecedency, precedence, precedency, priority
  Antonym:
  posteriority, subsequence, subsequentness
  

  source: wordnet30
• The state of being anterior or preceding in time or in situation; priority.(noun)

  source: webster1913