noun (n)

• similarity in appearance or character or nature between persons or things(noun.attribute)

  Synonym:
  alikeness, likeness
  Antonym:
  dissimilitude, unlikeness
  

  source: wordnet30
• a duplicate copy(noun.artifact)

  Synonym:
  counterpart, twin
  

  source: wordnet30
• The quality or state of being similar or like; resemblance; likeness; similarity; as, similitude of substance.(noun)

  source: webster1913