noun the theory or description of the universe, as a system displaying order and harmony.
2. cosmos ·noun the universe or universality of created things;
so called from the order and harmony displayed in it.
3. cosmos ·add. ·noun a genus of composite plants closely related to bidens, usually with very showy flowers, some with yellow, others with red, scarlet, purple, white, or lilac rays. they are natives of the warmer parts of america, and many species are cultivated. cosmos bipinnatus and c. diversifolius are among the best-known species; c. caudatus, of the west indies, is widely naturalized.