<p><strong>Noun</strong></p><ul><li>The third letter of the Greek alphabet (Γ, γ).</li><li>The consonant sound represented by this letter.</li><li>The third in a series of items.</li><li>Gamma, Astronomy: A star that is usually the third brightest of a constellation; the third brightest star in the Southern Cross is Gamma Crucis.</li><li>A unit of weight equal to one microgram.</li><li>Physics: A unit of magnetic field strength, equal to 10−5 gauss.</li><li>Photography: A measure of the degree of development of a negative or print.</li><li>Television: An analogous numerical indication of the degree of contrast between light and dark in the reproduction of an image in television.</li><li>Chiefly British: A grade showing that an individual student is in the third, or lowest, of three scholastic sections in a class.</li></ul>