A more thorough explanation:

Definition: Fiducial is an adjective that describes a situation where there is trust and confidence in another person or thing.

Example 1: When you go to a doctor, you have a fiducial relationship with them. You trust that they will take care of you and give you the right treatment.

Example 2: A fiducial marker is a small object that is placed in a patient's body during medical imaging. The doctor relies on the marker to accurately locate the area that needs treatment.

The examples illustrate the definition of fiducial by showing situations where trust and confidence are essential. In the first example, the patient trusts the doctor to provide the right treatment. In the second example, the doctor relies on the fiducial marker to accurately locate the area that needs treatment.