noun (n)

• the capacity to understand a broad range of topics(noun.cognition)

  Example:
  A teacher must have a breadth of knowledge of the subject.
  

  Synonym:
  comprehensiveness, largeness
  

  source: wordnet30
• the extent of something from side to side(noun.attribute)

  Synonym:
  width
  

  source: wordnet30
• Distance from side to side of any surface or thing; measure across, or at right angles to the length; width.(noun)

  source: webster1913