noun (n)

• natural or artificial channel through which water flows(noun.object)

  source: wordnet30
• a natural body of running water flowing on or under the earth(noun.object)

  Synonym:
  stream
  

  source: wordnet30
• a conduit through which water flows(noun.artifact)

  Synonym:
  waterway
  

  source: wordnet30
• One of the holes in floor or other plates to permit water to flow through.(noun)

  source: webster1913