Mathematics and Physics Glossary-- X --x2, n. (Arith.) The symbol meaning square the number that appears in the place of x. x3, n. (Arith.) the symbol meaning cube the number that appears in the place of x. X-axis, n. (Math.) (a) The horizontal axis of a two-dimensional Cartesian coördinate system. (b) One of three axes in a three-dimensional Cartesian coördinate system. X-ray tube (Phys.) A vacuum tube suitable for producing Röntgen rays. |