From The Collaborative International Dictionary of English v.0.48 :
Manometer \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. [1913 Webster] ManometricFrom WordNet (r) 3.0 (2006) :
manometer n 1: a pressure gauge for comparing pressures of a gas