A casual, an influential factor, or that which affects a decision: Because he had to carry all of the shopping bags, it was a determinative element in Ed's decision not to take an umbrella with him.

Used to describe a decisive or final behavior: Mr. Dean, the contractor, wrote out the determinative estimate and contract for the new driveway which would be made for the family.

The end result or goal toward which thoughts progress: One of the schizophrenic's disturbances of associations is an inability to keep to the determinative idea or to focus his or her attention on a central objective or purpose.