1. relating to lines: relating to, consisting of, or using lines
2. relating to straight line: relating to a straight line or capable of being represented by a straight line
3. changing proportionally: describes variables that change proportionally and are representable on a graph as a straight line There's no linear relation between mortality and size.
4. unimaginative: developed sequentially from the obvious without in-depth understanding takes a somewhat linear approach to the problem
5. graphic arts with clearly defined lines: relying for its visual effect on clearly defined lines rather than on color
6. mathematics of first degree: about or in the first degree relative to a mathematical variable
7. electronics with output varying as input does: with an output that varies directly with the input
8. botany long and narrow: describes a leaf that is long and narrow