migrainous Definition

a condition marked by recurring moderate to severe headache with throbbing pain that usually lasts from four hours to three days, typically begins on one side of the head but may spread to both sides, is often accompanied by nausea, vomiting, and sensitivity to light or sound, and is sometimes preceded by an aura and is often followed by fatigue

a condition that is a variant form of the typical migraine but in which headache is absent or not a prominent symptom:

a condition in which an aura involving visual disturbances (such as diplopia, scotoma, or tunnel vision) is the main symptom and is not followed by headache —called also acephalgic migraine, silent migraine