Question: what do x stand for?
Answer: X signifies the sun god, a simple-rayed sun or star. In clothing sizes, X means “extra,” as in “XS” for extra small, “XL” for extra-large, and so on. X in aerospace stands for “experimental." X is the diagnostic tool familiar to all of us as the X-ray. Vitamin X refers to the rave or dance club drug, Ecstasy.