A flagellate is an organism with one or more whip-like organelles called flagella. Some cells in may be flagellate, for instance the spermatozoa of most phyla. do not produce flagellate cells, but , , green algae, some gymnosperms and other closely related plants do. Likewise, most fungi do not produce cells with flagellae, but the primitive fungal do. Many take the form of single-celled flagellates.
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for the diameter of a sphere. The word "diameter" is derived from Greek language διάμετρος ( diametros), "diameter of a circle", from δια- ( dia-), "across, through" μέτρον ( metron), "measure". Online Etymology Dictionary It is often abbreviated ..
