Stacking (a.k.a. layering) means multiple sources of funding are used for one purpose (project). Each source of funding is tracked and reported separately.
Braiding means the stacked sources of funding are woven together. One funding source is used as match to another source. Each individual funding source maintains its specific program identity. Both must be tracked independently. However, the source used as match must be reported once to its original funder and a second time as part of the matched project.