Congenital anomaly: Something that is unusual or different at birth.
A minor anomaly is defined as an unusual anatomic feature that is of no serious medical or cosmetic consequence to the patient. A minor anomaly of the feet might, for example, be curvature of the second toe so it overlaps the third toe a little.
A major anomaly, by contrast, might be a cleft lip and palate, a birth defect of serious medical and cosmetic consequence to the child.
The word "congenital" means "at birth." "Anomaly" comes from the Greek word "anomalos" meaning "uneven" or "irregular."