The word "caca" is often used informally to refer to feces or excrement, usually in a child-friendly or humorous context. It can also be a way for young children to refer to something dirty or undesirable. In some cultures, it might be used to talk about poop in a less serious or more playful manner.
The term "caca" comes from the Spanish word for feces, which itself is a childlike or diminutive form derived from Latin. The word is often used in playful contexts, particularly in relation to young children.