Human Phenotype Ontology term HP_0007359 (Focal-onset seizure) can be described as follows. A focal-onset seizure is a type of seizure originating within networks limited to one hemisphere. They may be discretely localized or more widely distributed, and may originate in subcortical structures. Also known as: Focal onset seizure, Focal seizure, Focal seizures, Focal-onset seizures, Partial seizure, Partial seizures, Seizure affecting one half of brain.