What does taboo mean in the boy of the painted cave?

Oh, dude, in "The Boy of the Painted Cave," taboo basically means something that's forbidden or not allowed. It's like when your mom tells you not to eat cookies before dinner, but in ancient times, it could be way more serious, like not entering a sacred cave or messing with sacred rituals. So, yeah, taboo is just a fancy Word for "don't do that thing or else."