al·tim·e·ter  (āl-tĭm'ĭ-tər)  n. An instrument for determining elevation, especially an aneroid barometer used in aircraft that senses pressure changes accompanying changes in altitude. [Latin altus, high; see al-2 in Indo-European roots + -meter.] al'ti·met'ric (āl'tə-mět'rĭk) adj., al·tim'e·try n. |