Relating to the measurement of altitude or height; pertaining to an altimeter or the science of altimetry.
From altimetry (the science of altitude measurement) plus the adjective suffix -ical, creating an adjective meaning 'of or relating to altitude measurement.'
Altimetrical readings from weather balloons helped meteorologists discover the jet stream in the 1940s—invisible to the eye but visible through altitude data, revolutionizing weather prediction.
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