angiosperm (n.)

"plant with seeds contained in a protective vessel" (as distinguished from a gymnosperm, in which the seeds are naked), 1852, from Modern Latin Angiospermae, coined 1690 by German botanist Paul Hermann (1646-1695), from Greek angeion "vessel" (see angio-) + spermos, adjective from sperma "seed" (see sperm). So called because the seeds in this class of plants are enclosed. Related: Angiospermous.