noun (n)

• the interchange of sections between pairing homologous chromosomes during the prophase of meiosis(noun.process)

  Synonym:
  crossing over
  

  source: wordnet30
• a voter who is registered as a member of one political party but who votes in the primary of another party(noun.person)

  Synonym:
  crossover voter
  

  source: wordnet30
• the appropriation of a new style (especially in popular music) by combining elements of different genres in order to appeal to a wider audience(noun.communication)

  Example:
  A jazz-classical crossover album.
  

  source: wordnet30
• a path (often marked) where something (as a street or railroad) can be crossed to get from one side to the other(noun.artifact)

  Synonym:
  crossing, crosswalk
  

  source: wordnet30