any of several instruments for measuring and recording various bodily functions, as the velocity or volume of blood flow, heart rate or breathing rate, changes in the size of organs or limbs, etc.
Origin of plethysmographfrom Classical Greek pl?thysmos, a multiplying from pl?thymein, to increase from pl?thys, a crowd (akin to pl?thein: see plethora) + graph
An instrument that measures variations in the size of an organ or body part on the basis of the amount of blood passing through or present in the part.
Origin of plethysmographGreek plēthusmos increase ( from plēthūnein to increase ) ( from plēthūs quantity ) ( from plēthein to be full ; see pelə-1 in Indo-European roots.) -graph