- meterA device that measures things.
- metreThe basic unit of length in the International System of Units (SI: Système International d'Unités), equal to the distance travelled by light in a vacuum in 1/299 792 458 seconds. The metre is equal to 39+⁴⁷⁄₁₂₇ (approximately 39.37) imperial inches.
- heliometerAn astronomical instrument, based on a telescope, for measuring the diameter of the sun; now used to measure the angular distance between stars and other celestial bodies.