The term "Staining Panel" refers to a combination of parameters measured in a flow cytometry experiment.  Within each Staining Panel are "Channels", each of which measures some property about the events collected on the cytometer.  Some experiments might have more than one staining panel.  

It is common for a Staining Panel to be composed of Channels measuring fluorophore-conjugated antibodies. For example, a Staining Panel for T cells might measure CD3-FITC, CD4-PE, and CD8-APC.