aggregation (a greg ash on)

[ By "material aggregation " being meant the way in which, by nature or by art, the molecules of matter are arranged together. Tyndall. Wanting any great and acknowledged centre of national life and thought, our expansion has hitherto been rather aggregation than growth. Lowell, Study Windows, p. 83. 2. In logic, the union of species to form a genus, or of terms to form a term true of anything of which any of its parts are true, and only false when all its parts are false.-3. The adding of any one to an a ociation as a member thereof; affiliation. [Rare.] The second [book] recounts his aggregation to the society of free-masons. Monthly Rev., ΧΧ. 537. ( N. E. D. ) 4. A combined whole; an aggregate. In the United States of America a century hence we shall therefore doubtle have a political aggregation immeasurably surpa ing in power and in dimensions any empire that has as yet existed. J. Fiske , Amer. Pol. Ideas, p. 139. Creatures of inferior type are little more than aggrega tions of numerous like parts. H. Spencer , Social Statics, p. 493. 5. In bot., applied by Darwin specifically to the peculiar change induced in the cells of the tentacles of Drosera by mechanical or chemical stimulation. - Theorem of aggregation, in the theory of invariants, a theorem concerning the number of linearly independent invariants of a given type.