Vocabulary - 3D Shapes

The vocabulary surrounding 3D shapes is essential for understanding geometry, especially for KS2 students. Familiar shapes such as the 'cube' and 'cuboid' are examples of polyhedra, which are solid figures with flat faces. The 'pyramid', known for its pointed top and flat base, is another member of this group. These shapes are characterised by their 'vertices' (singular: 'vertex'), which are the corners where edges meet, and their 'faces', the flat surfaces that make up the exterior of the shape. Each face is enclosed by 'edges', the straight lines where two faces meet.

Moving on to other 3D shapes, we encounter the 'sphere', a perfectly round figure, and its relative, the 'hemisphere', which is essentially half a sphere. The 'cone' and 'cylinder' are also part of the 3D shape family, with the cone tapering to a point and the cylinder having two parallel circular faces. A 'prism' is a solid figure with two identical ends and flat sides, often used to describe shapes like triangular or hexagonal prisms. In describing these shapes, we also use terms like 'surface', which refers to the outer or inner boundary of a shape, and 'cross-section', which is the shape you get when you cut through a 3D object. Additional descriptors include 'flat' and 'curved', indicating the type of surface; 'straight' lines as opposed to 'curved' ones; and whether the shape is 'hollow' or 'solid'. Lastly, positional vocabulary such as 'horizontal', 'vertical', 'perpendicular', and 'parallel' helps to describe the orientation or the relationship between lines and surfaces within these shapes.