piezometer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An instrument for measuring pressure, especially high pressure.

from The Century Dictionary.

• noun An instrument for measuring the degree of resistance of the tissues of the body.
• noun Any instrument for ascertaining or testing pressure.
• noun An instrument for showing the compressibility of water or other liquid, and the degree of such compressibility under varying pressures.
• noun An instrument consisting essentially of a vertical tube inserted into a water-main, to show the pressure of the fluid at that point, by the height to which it ascends in the tube of the piezometer.
• noun A sounding-apparatus in which advantage is taken of the compression of air in a tube by the pressure of the water at great depths to indicate the depth of the water.
• noun An instrument for testing the pressure of gas in the bore of a gun.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Physics) An instrument for measuring the compressibility of liquids.
• noun (Physics) A gauge connected with a water main to show the pressure at that point.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An instrument used to measure pressure.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a measuring instrument for measuring high pressures