oximeter

noun

Etymology: From oxi- (variant of oxy-) + -meter. The word was first applied in sense 2 (“a device that measures the oxygen saturation of arterial blood”) by American physiologist Glenn Allan Millikan (1906–1947).

1. A device that measures the quantity of oxygen in something, particularly air in the atmosphere.

   “The instruments in which the oxigen gas of a determined quantity of air was ascertained, received the name of EUDIOMETERS, because they were considered as measurers of the purity of air. They are however more properly called OXIMETERS.”

   “Is it not to be regretted that the term eudiometry and eudiometer should be applied exclusively to the art of determining the quantity of oxygen in the air and the instruments for that purpose? Would not the terms oximetry and oximeter be more appropriate?—Tr[anslator].”

2. A device that measures the quantity of oxygen in something, particularly air in the atmosphere.

   “The Millikan oxymeter, with which Dr. Howard Bierman has been working and which he has discussed with this group, can be attached to the external ear and gives prompt information about oxygen saturation. It is so calibrated that the administration of 97 to 100% oxygen to normal individuals causes an increase of 5 per cent in the oxymeter reading.”

   “At 8 to 10 G, ear oximeter readings may fall to 75 percent saturation. The lungs, afterward, may show some atelectasis.”