Math Glossary Letter Z z score noun the number of standard deviations from the mean a data point is. Also known as a standard score z table noun The table of probabilities assigned to a z-score z-intercept noun A point at which a graph intersects the z-axis. zero noun A number with no size or quantity. Neither positive or negative.0 zero coupon bond noun A bond where the face value is paid at the time of maturity. No coupons are paid. zero matrix noun A matrix for which all elements are equal to 0. zero multiplication property noun The product of any number and zero is zeroA * 0 = 0 zero of a function noun A value of x which makes a function equal to 0. Note: A zero may be real or complex. zero slope noun The slope of a horizontal line. A horizontal line has slope 0 because all its points have the same y-coordinate. zero vector noun A vector with magnitude (length) zero. zeta noun A letter of the greek alphabet used for math notation.Ζ ζ zodiac sign noun an area of the sky that extends approximately 8° north or south of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year