Geometry Basics
Terms starting with S-T.

Knowing geometry basics can eliminate frustrations of a K-6 math student.  When there is just that one geometry term they don't recognize, or fully understand they probably wont be able to complete the question.  Allow them access to this great geometry dictionary to alleviate any problems they may be having.

This resource, online is entirely free.  However, if you would like to have a physical copy at home, off-line, for your student to have easy access to, please consider purchasing the e-book - Kindergarten to Sixth Grade Geometry Dictionary.

For just $5.95 - it is excellent value!

Geometry Basics - Words starting with S-T

Scale: To enlarge or reduce.

Scalene Triangle: A triangle where all three sides are different in length.

Sector:  A section of a circle defined by two radii and an arc.

Segment: A section of a circle defined by a chord and an arc.

Semicircle: Half a circle.

Septa: Prefix for 7. 

Septagon: A seven sided septagon.

Shape: A form or outline of an object.

 Side: The line or curve on the outside of a shape that joins the shapes vertices.

Size: How big or small something is. 

Solid: A three dimensional shape.

Solution: Answer to a problem.

Sphere: A three dimensional solid that is perfectly round - a ball.

Square: A quadrilateral with four equal sides, and four right angles.

Straight Angle: Any angle that equals 180 degrees.

Straight Line: The shortest distance between two points.

Supplementary angle: Two angles whose sum is 180 degrees.

Surface: A set of points that define a space.  A surface can be flat or curved.

Surface area: The total area of the surface of three dimensional object.

Symmetry: An object has symmetry when one half is a mirror image of the other.

Tangent: A straight line that touches a circle at only one point.

Tangram: A square cut into seven pieces.

Tessellation: Patterns created from shapes that fit together with no gaps.

Tetrahedron: A polyhedron with four triangular faces.  It is one of the 5 platonic solids.

Three-Dimensional: Has three dimensions - length, breadth and height.

Transformation: A change in position or size.  Can be created by, flipping, rotating, translating or enlarging.

Translation: Move an object in any direction without rotating it.

Trapezium: Quadrilateral with no parallel sides.

Tri: Prefix for 3.

Triangle: Three sided polygon.

Triangular prism: A prism whose base are two identical triangles and all other faces are rectangles.

Turn: Rotate around a fixed point.

Turning symmetry: Rotating an object about a point.

Two-Dimensional: Having only two dimensions - length and breadth.

If you searched this page for a geometry definition and did not find it - please contact me.
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