Final answer:
The Milky Way galaxy is the celestial event that has given its name to a chain of upscale gyms, symbolizing vastness and universal appeal.
Step-by-step explanation:
The celestial event that lends its name to a chain of upscale gyms is the Milky Way galaxy. The name 'Milky Way' has its origins in ancient Greek legend. In the field of astronomy, our Milky Way galaxy is composed of billions of stars and represents just one massive structure among countless others in the universe. Unlike folktales that vary across different cultures, the gym named after this galaxy aims to portray a sense of vastness and universal appeal, akin to its celestial namesake.