Also Mekometer. An instrument for the accurate measurement of distances by means of reflected polarized light.
Light elliptically polarized at a microwave frequency is beamed at a reflector at the distance to be measured, and the polarization of the reflected light is analysed to find the amount by which the distance of the reflector exceeds a whole number of modulation half-wavelengths.
Late 19th century (in an earlier sense). From ancient Greek μῆκος length + -meter.