<p><strong>Noun:</strong></p><ul><li>a body of coherent matter, usually of indefinite shape and often of considerable size: a mass of dough.</li><li>an abnormal lump in the body, often in the form of a cyst or tumor: The mass they removed was alarmingly large, but the great news is that it was benign.</li><li>a collection of incoherent particles, parts, or objects regarded as forming one body: a mass of sand.</li><li>a considerable assemblage, number, or quantity: a mass of troops.</li><li>a shape or three-dimensional volume that has or gives the illusion of having weight, density, and bulk.</li><li>the quantity of matter as determined from its weight or from Newton's second law of motion.</li><li>a preparation of thick, pasty consistency, from which pills are made.</li><li>the ordinary or common people as a whole: the working classes or the lower social classes.</li></ul><p><strong>Adjective:</strong></p><ul><li>pertaining to, involving, or affecting a large number of people: mass unemployment; mass migrations.</li><li>participated in or performed by a large number of people, especially together in a group: mass suicide.</li><li>reaching or designed to reach a large number of people: television, newspapers, and other means of mass communication.</li><li>done on a large scale or in large quantities: mass destruction.</li></ul><p><strong>Verb (used without object):</strong></p><ul><li>to come together in or form a mass or masses: The clouds are massing in the west.</li></ul><p><strong>Verb (used with object):</strong></p><ul><li>to gather into or dispose in a mass or masses; assemble: The houses are massed in blocks.</li></ul>