What is "tonometer"

Tonometer \To*nom"e*ter\, n. [Gr. ? a stretching, a tone + -meter.]

1. (Physics.) An instrument for determining the rate of vibrations in tones.

2. (Physiol.)

   1. An apparatus for studying and registering the action of various fluids and drugs on the excised heart of lower animals.

   2. An instrument for measuring tension, esp. that of the eyeball.

n. An instrument used to measure tension or pressure, especially inside the eye.

n. measuring instrument for measuring tension or pressure (especially for measuring intraocular pressure in testing for glaucoma)