In this context, the "Live View Axis" refers to the interactive gizmos and coordinate systems displayed directly in the viewport that allow artists to manipulate objects in 3D space.
At its core, a refers to the dynamic, continuously updating reference line on a graph or chart that represents the "present moment." Unlike static charts where the X-axis (usually time) has a fixed start and end point, a Live View Axis shifts relentlessly to the left, pushing historical data out of view as new data points stream in from the right.
Imagine a live protest: A journalist sees the police line (Spatial Axis A). A medic sees body temperature overlays (Semantic Axis B). A historian watching from home selects Temporal Axis -2 hours to see how the crowd assembled. All are watching the same continuous live event, but each axis reveals a different truth.