On the other end of the spectrum, the materials with the lowest conductivities, or best insulators, are glass, ceramic, rubber and some plastics. Not all materials are classified as insulators or conductors, because in the real world, they don't do a particularly good job of either one.
The point where the graph of a function crosses the x-axis or y-axis. y-intercept. The point where the graph crosses the y-axis. In a linear equation of the form y=mx+b. The y-intercept is the constant b. constant of proportionality. The constant ratio between two quantities. EX: 1/4, 2/8, 3/26.
1 A y-intercept of 3 means that a line's graph intersects the Y-axis at the point (0,3).  A y-intercept of -4 means that the graph of a line crosses the Y-axis at the point (0,-4).