What is the definition of multidirectional transport

Xylem transport is only unidirectional while transport through phloem is multi-directional.

But minerals are taken up by xylem from the surrounding tissues actively, and even though they flow along with the water column, they are actively unloaded near 'sink' sites. Sometimes, minerals are also taken up from aging parts and transported to growing areas of the plant. Then shouldn't mineral transport through xylem be multi directiona