An appraisal or diagnosis by a knowledgeable professional, such as a lawyer or physician, who has been consulted in order to confirm or disconfirm the advice or view of another person previously consulted
After my doctor told me that my illness was psychosomatic, I sought a second opinion.
If you get a second opinion, you ask another qualified person for their opinion about something such as your health. I would like a second opinion on my doctor's diagnosis