Why is the Debye Hückel Limiting Law called the "limiting law"?
The Huckel limiting law allows us to determine the activity coefficient of an ion in a dilute solution of a known ionic strength.

Here's an appealing answer which makes perfect sense to me that I found on EveryScience


  The name 'limiting law' is applied because in the limit of arbitrarily low molalities (ie as the concentration of the solute gets
  closer and closer to zero), all solutions are expected to behave in a
  manner consistent with the expression.