- Fistula: An abnormal passage or connection between two organs or blood vessels.
- Focal Seizure: Seizure arising from one part of the brain.
- Forme Fruste: An atypical form of a disease, a variation of the disease.
- Frontal Lobe: Most forward lobe of the brain. Deals with higher cognitive function (i.e. planning, organizing, etc.). Contains the motor cortex.