\Ma*nom"e*ter\, n. [Gr. ? thin, rare + -meter: cf. F.
manom[`e]tre.]
An instrument for measuring the tension or elastic force of
gases, steam, etc., constructed usually on the principle of
allowing the gas to exert its elastic force in raising a
column of mercury in an open tube, or in compressing a
portion of air or other gas in a closed tube with mercury or
other liquid intervening, or in bending a metallic or other
spring so as to set in motion an index; a pressure gauge. See
{Pressure}, and Illust. of {Air pump}.