Body plethysmography, also known as whole-body plethysmography, is a type of lung function testing used to measure lung volume and airway resistance. However, there are several synonyms for this medical term that you might come across. Alternative terms for a body plethysmograph include thoracic gas volume meter, spirometer, respiratory box, and lung function chamber. These synonyms relate to the equipment used in the procedure, as the device measures the volume of air in the lungs and the related pressure changes. While body plethysmography may sound complicated, it is a common and useful test for diagnosing breathing conditions and understanding lung function.