plethysmograph
Concise Oxford English Dictionary © 2008 Oxford University Press:
plethysmograph /plɪˈθɪzməgrɑːf/
▶noun Medicine an instrument for measuring variation in the volume of a part of the body caused by changes in blood pressure.
– derivatives
plethysmographic adjective.
plethysmographic adjective.
'plethysmograph' also found in these Oxford entries:

