Convergency

n.
  1. The condition or quality of converging; tendency to one point; the occurrence of two or more things coming together.
  2. (Math.) the approach of an infinite series to a finite limit.
  3. a representation of common ground between theories or phenomena.
  4. the act of converging (coming closer).
  5. (Biol.) a similarity of form or function in two or more organisms caused by evolutionary adaptations to a similarity in the environment, rather than to a common heredity.