noun (n)

• the act of arousing an organism to action(noun.act)

  source: wordnet30
• any stimulating information or event; acts to arouse action(noun.cognition)

  Synonym:
  input, stimulant, stimulus
  

  source: wordnet30
• (physiology) the effect of a stimulus (on nerves or organs etc.)(noun.process)

  source: wordnet30
• mutual sexual fondling prior to sexual intercourse(noun.act)

  Synonym:
  arousal, foreplay
  

  source: wordnet30
• The act of stimulating, or the state of being stimulated.(noun)

  source: webster1913