A division of eukaryotic, photosynthetic, nonflowering organisms that includes many seaweeds. [pl. of L. alga, seaweed]
* * *
al·gae (alґje) [L., pl., “seaweedsâ€] a large group included in the kingdom Protista, now classified into several different phyla. They are cryptogamous plantlike organisms in which the body is unicellular or consists of a thallus. Algae include the seaweeds and many unicellular fresh-water plants, most of which contain chlorophyll, and they account for about 90 per cent of the earth's photosynthetic activity. algal adjMedical dictionary. 2011.