Aristotle's Four Causes:

Four answers to the question: "Why is <x> here?"

Material: "It's here because there is matter to make it out of." The material cause is simply the stuff that comprises everything.
Formal: "It's here because someone had an idea." Think of this as the "blueprint". Everything has a form or pattern. This is the essence of the thing.
Efficient: "It's here because I put it here or made it" Notice that this one is really two answers. The thing is here because I, or someone, moved it here. And, it is here because someone made it.
Final: "It's here because we needed a thing just like it for something." If the thing is a chair, we needed something to sit on. If it is a pen, we needed something to write with. In other words, a thing's purpose is also a cause.

Aristotle's 4 causes, explained using snickerdoodles