noun (n)

• a point of convergence of light (or other radiation) or a point from which it diverges(noun.phenomenon)

  Synonym:
  focus
  

  source: wordnet30
• a central point or locus of an infection in an organism(noun.state)

  Synonym:
  focus, nidus
  

  source: wordnet30
• the concentration of attention or energy on something(noun.cognition)

  Synonym:
  centering, direction, focus, focusing, focussing
  

  source: wordnet30