Source : Webster's Revised Unabridged Dictionary (1913)

   {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 a 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.