@urangutan,
I'm glad someone brought up
coordinates. This is the way I see it for now, but I expect to be corrected as I study further...
1st dimension: linear, coordinate signified by (x) along single axis x
2nd dimension: planar, coordinates signified by (x,y) on plane containing 2 intersecting lines x and y
3rd dimension: spatial, coordinates signified by (x,y,z) on 3-d grid made possible by addition of line z perpendicular to the x,y plane
4th dimension: time, coordinates signified by (x,y,z,t) also known as an event...even a stationary object at location (x,y,z) is given different coordinates as t changes
5th dimension: ?????
The pattern seen here is that when a point on a given dimension is kept fixed at its coordinate(s), the addition of the next dimension allows it to remain fixed while "escaping" the grid of the prior dimension. (I know I explained this terribly...)
For example, take any point on the planar grid (x,y). Fix their values. Add the z-axis. Given the fixed coordinates of (x,y), a z value now allows us to locate a point outside of the x,y plane. The t value allows the same for spatial coordinates (x,y,z) thus differentiating an event from a simple spatial location.