| UNDECAGON | Two-dimensional geometric figure having eleven sides and internal angles of about 147.27degrees (9) |
| HENDECAGON | In geometry, a closed plane figure having eleven sides and eleven angles (10) |
| ICOSAGON | In geometry, a plane figure with twenty sides and internal angles of 162degrees (8) |
| EQUILATERAL | The type of triangle with sides of the same length and internal angles of the same magnitude |
| CUBE | Three-dimensional geometric figure that is the only regular hexahedron (4) |
| HENDECANE | A saturated aliphatic hydrocarbon, having 11 carbon atoms (9) |
| OUD | Fretless Arabian musical instrument resembling the lute, having 11 strings and a pear-shaped body (3) |
| CONES | Tapering three-dimensional geometric figures resembled by bollards, funnels, ice cream-filled wafers, party hats or volcanic hills |
| ELLIPSOIDS | Three-dimensional geometric figures |
| ENFORCE | Compel eleven sides in favour of confederate borders (7) |
| ENCOUNTERING | Coming up against eleven sides opposing (12) |
| SPHERICON | Three-dimensional geometric solid with a single continuous face and two edges |
| SNELLSLAW | Formula relating to the angles of incidence and refraction, used in the field of optics (6,3) |
| DODECAGON | Closed plane figure having twelve sides and twelve vertices (points) (9) |
| CHILIAGON | In geometry, a closed plane figure having 1000 sides (9) |
| ALTITUDES | Angles of elevation above the horizon (9) |
| REGULAR | Of a geometric figure, having all sides and all angles equal (7) |
| SQUARE | A geometric figure having four equal sides and four right angles (6) |
| NONAGON | Closed plane geometrical figure that has internal angles of 140degrees (7) |
| NONAGONS | Regular ____ have internal angles of 140 degrees |
