noun (n)

• the perception that something has occurred or some state exists(noun.cognition)

  Example:
  Early detection can often lead to a cure.
  

  Synonym:
  sensing
  

  source: wordnet30
• the act of detecting something; catching sight of something(noun.act)

  Synonym:
  catching, espial, spotting, spying
  

  source: wordnet30
• the detection that a signal is being received(noun.communication)

  Synonym:
  signal detection
  

  source: wordnet30
• a police investigation to determine the perpetrator(noun.act)

  Example:
  Detection is hard on the feet.
  

  Synonym:
  detecting, detective work, sleuthing
  

  source: wordnet30
• The act of detecting; the laying open what was concealed or hidden; discovery; as, the detection of a thief; the detection of fraud, forgery, or a plot.(noun)

  source: webster1913