Main Entry: to·nom·e·ter

Pronunciation: \tō-ˈnä-mə-tər\

Function: noun

Etymology: Greek tonos tone + English -meter

Date: 1725

1 : an instrument or device for determining the exact pitch or the vibration rate of tones
2 : an instrument for measuring tension or pressure and especially intraocular pressure

— to·nom·e·try \tō-ˈnä-mə-trē\ noun