**Lin"e*ar** (?), a. [L. *linearis*, *linearius* , fr. *linea* line: cf. F. *lin'eaire*. See 3d Line.]

**1.**

Of or pertaining to a line; consisting of lines; in a straight direction; lineal.

**2.** Bot.

Like a line; narrow; of the same breadth throughout, except at the extremities; as, a **linear** leaf.

Linear differential Math., an equation which is of the first degree, when the expression which is equated to zero is regarded as a function of the dependent variable and its differential coefficients. -- Linear equation Math., an equation of the first degree between two variables; -- so called because every such equation may be considered as representing a right line.<-- = stright line! --> -- Linear measure, the measurement of length. -- Linear numbers Math., such numbers as have relation to length only: such is a number which represents one side of a plane figure. If the plane figure is square, the linear figure is called a *root*. -- Linear problem Geom., a problem which may be solved geometrically by the use of right lines alone. -- Linear transformation Alg., a change of variables where each variable is replaced by a function of the first degree in the new variable.

© Webster 1913.