noun (n)

• any entry into an area not previously occupied(noun.event)

  Synonym:
  encroachment, invasion
  

  source: wordnet30
• entrance by force or without permission or welcome(noun.act)

  source: wordnet30
• the forcing of molten rock into fissures or between strata of an earlier rock formation(noun.process)

  source: wordnet30
• rock produced by an intrusive process(noun.object)

  source: wordnet30
• entry to another's property without right or permission(noun.act)

  Synonym:
  encroachment, trespass, usurpation, violation
  

  source: wordnet30
• The act of intruding, or of forcing in; especially, the forcing (one's self) into a place without right or welcome; encroachment.(noun)

  source: webster1913