This means that if you die due to an accident this insurance policy may pay out a death benefit.
However, there is usually a limit as to when you die after the accident. For instance, you may have to die within 3 or 6 months of the accident in order for the policy to pay out a death benefit.
If you lose a leg, arm, hand, etc. and survive the accident there may be a benefit paid to you, as well.
Life insurance differs from AD&D in that it pays the face amount (death benefit) of the life insurance policy when the insured dies providing the cause of death was not excluded in the life insurance policy.
Learn more about how accidental death insurance works.