A more thorough explanation:

Term: Dispositive
Definition: Dispositive means something that is very important and can make a final decision. It can also refer to the way property is given away in a will or deed.
Examples:

• The DNA evidence was dispositive in proving the suspect's guilt.
• The dispositive clause in the will stated that the entire estate would go to the eldest son.

The first example shows how the DNA evidence was the deciding factor in proving the suspect's guilt. The second example shows how the dispositive clause in the will determined how the property would be distributed.