noun (n)

• an increase in width(noun.process)

  Synonym:
  broadening
  

  source: wordnet30
• a part of a road that has been widened to allow cars to pass or park(noun.artifact)

  Synonym:
  turnout
  

  source: wordnet30
• the act of making something wider(noun.act)

  Antonym:
  narrowing
  

  source: wordnet30