This page gathers the 757 dictionary entries belonging to the domain “Geometry”, as labelled by Wiktionary. Each word leads to its full entry: definitions, etymology, pronunciation, examples. Page 7 of 8: from “semiregular” to “trapezohedron”.
- semiregular adj Uniform (isogonal and isotoxal) with regular faces of two or more types, such that each vertex is surrounded by the same polygons in the…
- semiregular polyhedron noun A polyhedron whose faces are all regular polygons, two or more having a different amount of sides, and each vertex having the same…
- semisquare noun A right isocoles triangle, or such figure of which two form a square.
- sextant noun One sixth of a circle or disc; a sector with an angle of 60°.
- shape noun A geometric figure defined by its surfaces, lines, and angles, existing in 2D or 3D
- silver ratio noun The irrational number (approximately 2.414), which is equal to the sum of its own reciprocal and two. It equals one plus the square root of…
- similarity noun A transformation (of a Euclidean space) that preserves angles and the ratios of distances
- similitude noun A similarity: a transformation of Euclidean space that preserves angles and the ratios of distances.
- simplex noun A generalization of a triangle or tetrahedron to an arbitrary dimension; more accurately, the convex hull of n+1 affinely independent…
- Simson line noun Given a triangle ABC and a point P on its circumcircle, the three closest points to P on lines AB, AC, and BC are collinear. The line…
- sinistrorse adj Having a positive torsion.
- skeleton noun The vertices and edges of a polyhedron, taken collectively.
- skew adj Of two lines in three-dimensional space: neither intersecting nor parallel.
- slab noun A region between two parallel lines in the Euclidean plane, or between two parallel planes in three-dimensional Euclidean space, or between…
- snub cube noun An Archimedean solid with thirty-eight faces, of which six are squares (no two of which share a vertex) and thirty-two are equilateral…
- solid noun A three-dimensional figure (as opposed to a surface, an area, or a curve).
- solid angle noun The three-dimensional analog of an angle, equivalent to the area of that portion of the surface of a unit sphere that it subtends.
- solidity noun The solid contents of a body; volume; amount of enclosed space.
- space noun A set of points, each of which is uniquely specified by a number (the dimensionality) of coordinates.
- spectrum noun An abstract object in mathematics created from a commutative ring R and denoted operatorname Spec(R) or operatorname SpecR and said to be…
- sphenocorona noun A polyhedron, one of the Johnson solids, whose faces are composed of 12 equilateral triangles and 2 squares.
- sphere noun The set of all points in three-dimensional Euclidean space (or n-dimensional space, in topology) that are a fixed distance from a fixed…
- spherical adj Shaped as a sphere; being a sphere.
- spherical angle noun A particular dihedral angle, the angle between two intersecting arcs on a sphere, measured by the angle between the planes containing the…
- spherical excess noun The amount by which the sum of the three angles of a spherical triangle exceeds two right angles. The spherical excess is proportional to…
- spherical geometry noun The geometry of the 2-dimensional surface of a sphere;
- spherical lune noun A portion of the surface of a sphere cut off by two vertical planes through the centre of the sphere.
- sphericity noun The ratio of the surface area of a given particle to the surface area of a sphere with the same volume.
- sphericon noun A solid constructed by slicing a bicone with 90-degree apices through a plane containing both of them, rotating one half by 90 degrees, and…
- spheroconic noun A non-plane curve formed by the intersection of the surface of an oblique cone with the surface of a sphere centred at the cone's vertex.
- spindle noun A solid generated by the revolution of a curved line about its base or double ordinate or chord.
- spiral noun A curve that is the locus of a point that rotates about a fixed point while continuously increasing its distance from that point.
- spire noun The part of a spiral generated in one revolution of the straight line about the pole.
- spiric noun A curve, the plane section of a torus.
- spiroid adj Resembling or having the form of a spiral or helix.
- splitter noun A line segment through one of the vertices of a triangle that bisects the perimeter of the triangle.
- spread noun An unlimited expanse of discontinuous points.
- square noun A polygon with four straight sides of equal length and four right angles; an equilateral rectangle; a regular quadrilateral.
- square pyramid noun A three-dimensional geometric figure with a square base and four triangular sides that connect at one point. An example is the Great…
- square the circle verb To construct a square with the same area as a given circle by using only a finite number of steps with compass and straightedge, a task…
- squared adj Covered with a grid of squares.
- squarely adv In the shape of a square; at right angles.
- squircle noun A closed quartic curve having properties intermediate between those of a square and a circle.
- star noun A star-shaped ornament worn on the breast to indicate rank or honour in a military. Now often used metonymically for military rankings.
- star polygon noun A geometric figure formed by connecting, with straight lines, every vertex of a p-sided regular polygon to the qth vertex beyond it…
- starlike adj Convex; having the property that any line segment joining any mapped point to a specified point in the domain lies entirely in the domain.
- Steiner point noun The point on the circumcircle of a triangle that lies at the intersection of three lines through the vertices of the triangle, where those…
- Steinmetz solid noun The solid body generated by the intersection of two or three cylinders of equal radius at right angles.
- stellate verb To extend the edges or planes of a polyhedron to form a new shape.
- stellated adj Of a polyhedron, having its edges or planes extended to form a new shape.
- steradian noun In the International System of Units, the derived unit of solid angle; the solid angle subtended at the centre of a sphere of radius r by a…
- sterication noun An operation in any dimension that cuts a regular polytope at its cells, its faces, its edges and its vertices, creating a new facet in…
- straight line noun A line with no curvature; a line with constant direction. The path of shortest length between two points.
- striction noun The definition of a geometric shape as all points with some relationship to a central point, curve, etc., for example, a circle is the…
- subcontrary adj Having, or being in, a contrary order; said of a section of an oblique cone having a circular base made by a plane not parallel to the…
- subnormal noun That part of the axis of a curved line which is intercepted between the ordinate and the normal.
- subtendent noun The side that subtends (is opposite) a specified angle;
- subtense noun A line which subtends, especially the chord of an arc.
- superdisk noun A closed curve, of form y = (1-xⁿ)^(1/n) (where n > 2), having properties intermediate between those of a circle and a square
- superellipse noun a geometric shape constituting a transition between a rectangle and a circle; a closed curve, of which the circle and ellipse are special…
- superellipsoid noun A closed surface, of which the sphere and ellipsoid are special cases, whose parametric equation is x = a.cos^(2/r)t, y = b.cos^(2/r)t, z =…
- superficies noun The area of a two-dimensional surface.
- superposability noun congruence
- supplement noun An angle that, when added to a given angle, makes 180°; a supplementary angle.
- surface noun The locus of an equation (especially one with exactly two degrees of freedom) in a space of more than two dimensions.
- surface area noun The total area on the surface of an object.
- symmedian noun Any of three lines associated with every triangle, constructed by taking a median of the triangle (a line connecting a vertex with the…
- symmetral noun (geometry)
- symmetry group noun A group whose elements are all the transformations under which a given object remains invariant and whose group operation is function…
- symptosis noun The meeting of polars of the same point with reference to different loci.
- tacnode noun A point of a curve where two or more osculating circles to the curve at that point are tangent, so that two branches of the curve have…
- tangent adj Touching a curve at a single point but not crossing it at that point.
- taxi distance noun Synonym of taxicab distance.
- taxicab distance noun The distance between two points on a grid, where the only path allowed is along horizontal and vertical lines.
- taxicab geometry noun A non-Euclidean geometry in which the distance between two points is the sum of the absolute differences between their corresponding…
- Teichmüller space noun A space T(S) assigned to a (real) topological (or differential) surface S: it parameterizes complex structures on S up to the action of…
- term noun A point, line, or superficies that limits.
- tessellate verb to cover a two-dimensional shape, such that multiple copies of itself placed edge to edge cover an area leaving no space between the shapes.
- tesseract noun The four-dimensional analogue of a cube; a 4D polytope bounded by eight cubes (analogously to the way a cube is bounded by six squares).
- tet adj Tetrahedral.
- tetragon noun Quadrilateral.
- tetrahedron noun A polyhedron with four faces; the regular tetrahedron, the faces of which are equal equilateral triangles, is one of the Platonic solids.
- tetrakis hexahedron noun A Catalan solid that has 24 congruent triangular faces and 36 edges and can be imagined as a cube with a square pyramid on each face.
- tiling noun A tessellation; the covering of a plane with shapes, without overlaps or gaps.
- tomahawk noun A geometric construction consisting of a semicircle and two line segments that serves as a tool for trisecting an angle; so called from its…
- tooth noun An irreducible component of a comb that intersects the handle in exactly one point, that point being distinct from the unique point of…
- tore noun The surface described by the circumference of a circle revolving about a straight line in its own plane.
- toric adj Which, in any of several technical senses, admits a high degree of symmetry, allowing combinatorial methods to be used in its study.
- torus noun A topological space which is a product of two circles.
- touchpoint noun A point where things touch.
- trace noun The intersection of a plane of projection, or an original plane, with a coordinate plane.
- tractory noun A tractrix.
- tractrix noun A curve that satisfies the following property: that segment of the tangent line that lies between the point of tangency and a fixed line…
- transflection noun A transfiguration consisting of reflection about a line combined with translation along the same line.
- translationary adj Pertaining to the shifting of coordinate axes.
- transversal noun A line intersecting a pair of parallel lines.
- transverse noun The longer, or transverse, axis of an ellipse.
- trapeze noun A trapezium.
- trapezium noun A quadrilateral with two sides parallel.
- trapezohedron noun Any of a class of polyhedra that have kite-shaped faces and are dual polyhedra of antiprisms.