Endpoint

The point at which a process is stopped because a predetermined value of a measurable variable is reached; the endpoint of an ion exchanger water softener service run is the point at which the hardness of the softener effluent increases to a predefined concentration, often 1.0 grain per gallon; the endpoint of a filter service may be the point at which the pressure drop across the filter reaches a predetermined value; the endpoint of a titration is the point at which the titrant produces a predetermined color change, pH value, or other measurable characteristic.