Webster's Revised Unabridged Dictionary · 1913

Hypochondriasis

Hypochondriasis , noun

[New Latin So named because supposed to have its seat in the hypochondriac regions. See Hypochondriac, Hypochondrium, and compare Hyp, 1st Hypo.]

(Medicine) A mental disorder in which melancholy and gloomy views torment the affected person, particularly concerning his own health; a morbid and deluded belief that one is afflicted with disease.