Primarily, yes, although there are journals that (additionally) ask for other publication fees, like page charges, or for imagery. But yes, primarily "Article P

Primarily, yes, although there are journals that (additionally) ask for other publication fees, like page charges, or for imagery. But yes, primarily "Article Processing Charges". Although that said, with some more layers of indirection, the same holds true for subscription fees: libraries have to keep paying those, because authors keep letting publishers lock away their research outputs behind paywalls, because they get reputation in return. And those subscription fees are equally outrageous.