| Word | Meaning |
| Cone | A solid with a circular base and a curved surface meeting at one point |
| Vertex | The pointed tip of a cone |
| Vertical height | Perpendicular distance from the vertex to the centre of the base, \( h \) |
| Slant height | Distance from the vertex along the surface to the rim, \( l \) |
| Sector | Part of a circle between two radii and an arc |
| Arc | A part of the circumference of a circle |
| Curved surface area (CSA) | Area of the curved surface only, \( \pi r l \) |
| Total surface area (TSA) | Base and curved surface together, \( \pi r (r + l) \) |