Manometer

[muh-nom-i-ter] /məˈnɒm ɪ tər/

noun
1.
an instrument for measuring the pressure of a fluid, consisting of a tube filled with a liquid, the level of the liquid being determined by the fluid pressure and the height of the liquid being indicated on a scale.
/məˈnɒmɪtə/
noun
1.
an instrument for comparing pressures; typically a glass U-tube containing mercury, in which pressure is indicated by the difference in levels in the two arms of the tube
n.

1730, from French manomètre (1706), said to have been coined by French mathematician Pierre Varignon (1654-1722) from Greek manos “thin, rare; loose in texture, porous; scanty, few” (see mono-) + -mètre (see -meter). Related: Manometric.

manometer ma·nom·e·ter (mā-nŏm’ĭ-tər)
n.

man’o·met’ric (mān’ə-mět’rĭk) or man’o·met’ri·cal adj.
ma·nom’e·try n.
manometer
(mə-nŏm’ĭ-tər)

An instrument used to measure the pressure exerted by liquids and gases. Pressure is exerted on one end of a U-shaped tube partially filled with liquid; the liquid is displaced upwards on the other side of the tube by a distance proportional to the pressure difference on each side of the tube.