Number 3

123456
Across
  1. 3. a reason for an action or condition
  2. 5. a distinguishing trait, quality, or property
  3. 6. class or division of people or things regarded as having particular shared characteristics
Down
  1. 1. a title or brief explanation appended to an article, illustration, cartoon, or poster
  2. 2. the distinctive nature of something
  3. 4. a quotation from or reference to a book, paper, or author