2D shapes are flat and have only length and width, like a square or a circle. 3D shapes are solid and have depth too, like a cube or a sphere.
A face is a surface of a solid shape, an edge is the line where two faces meet, and a vertex is a corner where edges meet. A cube has 6 faces, 12 edges and 8 vertices.
Perimeter is the distance all the way round a shape. Area is the space inside it. A rectangle 4 by 5 has a perimeter of 18 and an area of 20.
A flat pattern that folds up to make a 3D shape. The net of a cube is six squares joined together.