n. (Astron.) Either of two conspicuous celestial nebulae near the south celestial pole, resembling thin white clouds, each of which is a galaxy{ 2 } smaller than but separate from the Milky Way galaxy, and together they are the galactic formations nearest to our galaxy. They are not visible from the northern hemisphere, and are named after Ferdinand Magellan, who saw them in his expedition, which passed through the Strait of Magellan in South America, and one ship of which completed the first circumnavigation of the globe. [ 1913 Webster ]