Does “variable load” mean that a structure can take that load at any given area each at a time or all at the same time?

Most of the time a variable load is a variable distributed load, VDL as opposed to a uniform distributed load, UDL. The variable changes from one rate to another which is either greater or less than the first. This represented as a wedge.

Cases were this comes in is where loads are applied at an angle such as roof wedges.