The mysterious 4th dimension

Imagine we have a 2D plane-what would be the axis of the next,third dimension?Let's draw a line perpendicular to that plane.It's obvious that this line would be also perpendicular to every possible line in that plane,and also It's parallel to the third axis.
Now-wouldn't the axis of the 4th dimension have to be perpendicular to every possible line in 3D space?Is my reasoning correct,/sci/?

>>14
But c*t is a distance.  This is a common standard in GR and particle physics (which is also why particle masses are often given in eVs).