a rank in the Royal Navy comparable to that of a private in the army
noun 1. Optics, Crystallography. the part of a doubly refracted ray whose velocity within a crystal is the same in any direction. noun 1. the plane-polarized ray of light that obeys the laws of refraction in a doubly-refracting crystal Compare double refraction, extraordinary ray
noun 1. British. a share of common stock.
noun 1. British. .
noun 1. Radio. (of the two waves into which a radio wave is divided in the ionosphere under the influence of the earth’s magnetic field) the wave with characteristics more nearly resembling those that the undivided wave would have exhibited in the absence of the magnetic field.