Plethysmograph
Pronunciation : Pleth"ys*mo*graph
Part of Speech : n.
Etymology : [Gr. -graph.] (Physiol.)
Definition : Defn: An instrument for determining and registering the variations in the size or volume of a limb, as the arm or leg, and hence the variations in the amount of blood in the limb. -- Pleth`ys*mo*graph"ic, a.
Source : Webster's Unabridged Dictionary, 1913