Although favorable conditions for tornadoes in the United States can occur at any time, they are most common in spring and least common in winter. Because spring is a transitional period for the climate, there are more chances of cooler air meeting with warmer air, resulting in more thunderstorms.
linear. 1  of or relating to a line or lines. 2  made of or using lines: linear design. 3  in relation to length only; extended in a line.  designating or of a style of art in which forms are sharply delineated and line is emphasized over color, light and shadow, etc.
System of Linear Equations Definition. A set of n equations with n unknown variable with linear degree (one degree) are called linear systems. A linear equation is an equation involving one or more variables in which only the operations of multiplication by real numbers and summing of terms are allowed. Several linear equations involving the same variables are considered together is making a system of linear equations.