inductive definition

A recursive definition or inductive definition is one that defines something in terms of itself (that is, recursively), albeit in a useful way. For it to work, the definition in any given case must be well founded, avoiding an infinite regress.The difference between a circular definition and a recursive definition is that a recursive definition must have base cases, cases that satisfy the definition without being defined in terms of the definition itself, and all other cases comprising the definition must be "smaller" (closer to those base cases that terminate the recursion).
See more at Wikipedia.org...