Appropriation is taking a piece of art from someone else and adding your own touch to it. The piece can be directly taken or recreated in some shape or form. Some will perceive this as plagiarism, because no credit is given to the original artist. To me, most of the time appropriation is not plagiarism if the 2 pieces are visually different and/or have different ideas. When a piece is directly stolen with the same ideas without credit given, it is plagiarism.