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Now updated for CSW15. New words, if any, and new inflections of existing words, are shown in red.


agonic making no angle.
antiparallel making with a transverse line an internal angle equal to the external angle made by another line; (noun) an antiparallel line.
apothem (Greek) the perpendicular from the centre of a regular polygon to any of its sides.
arc a part of the circumference of a circle or other curve; (verb) to form an arc.
arccosine a mathematical function.
arcmin 1/60 of a degree of angle.
arcminute a unit of angular measurement, one sixtieth of a degree.
arcsec a unit of angle measurement, 1/3600 of a degree.
arcsine a geometrical ratio.
arctangent a geometrical ratio.
asymmetry lack of symmetry.
axis (Lat.) the imaginary straight line about which a body such as the earth rotates the white-spotted deer of India
axised having an axis.
bilinear of or involving two lines.
bisector one who, or that which, bisects; esp in geometry a straight line which bisects an angle.
brachypinakoid a pinakoid or prism parallel to the brachydiagonal.
brachyprism a prism parallel to the brachydiagonal.
catenoid the surface generated by rotating a catenary about its axis.
cathetus (Greek) a straight line perpendicular to another straight line or surface.
chiliagon (Greek) a plane figure of a thousand angles and sides.
chiliahedron (Greek) a one-thousand sided solid figure.
circumcenter the point at which the perpendicular bisectors of the sides of a triangle intersect and which is equidistant from the three vertices.
circumcentre the point at which the perpendicular bisectors of the sides of a triangle intersect and which is equidistant from the three vertices.
circumcircle a circle which passes through all the vertices of a polygon, such as a triangle.
coaxial having the same axis.
coaxially (Adv.) COAXIAL, having the same axis.
cofunction a kind of trigonometric function.
colinear in the same straight line.
colinearity the state of being colinear.
collimation the act of making parallel.
collinear in the same straight line.
collinearly (Adv.) COLLINEAR, in the same straight line.
conic cone-shaped, conical (noun) a conic section
conoidic nearly, but not exactly, conical.
conoidical nearly, but not exactly, conical.
coplanar on the same plane.
coplanarity the state of being coplanar.
cosec (Short for) cosecant, the secant of the complement of an arc or angle.
cosecant the secant of the complement of an arc or angle.
cosech (Short for) hyberbolic cosecant.
cosine a trigonometric function of an angle.
cotan (Short for) cotangent, the tangent of the complement of an arc or angle.
cotangent the tangent of the complement of an arc or angle.
coth (Short for) hyperbolic cotangent.
coversed as in coversed sine, an obsolete function in trigonometry.
coversine a function in trigonometry.
crunodal relating to a crunode, the point at which a curve crosses itself.
crunode the point at which a curve crosses itself.
cubage the process of finding the cubic content of a body.
cubature the determination of the cubic content of a solid.
cubic in the form of a cube (noun) a cubic equation
cubicly (Adv.) CUBIC, in the form of a cube.
decagon a plane figure with ten equal sides.
decagonal of a plane figure, having ten sides.
decagonally (Adv.) DECAGONAL, of a plane figure, having ten sides.
decahedral having ten sides.
decahedron a solid figure or body inclosed by ten plane surfaces.
declinator an instrument for taking the declination or angle which a plane makes with the horizontal plane.
diallel meeting and intersecting, as lines; not parallel; (noun) a scheme of cross-breeding within a select group of parents, designed to produce various hybrids with different genetic properties.
diameter a straight line passing through the center of a circle and ending at the periphery.
diametral pertaining to a diameter.
diametrally (Adv.) DIAMETRAL, pertaining to a diameter.
diametric pertaining to a diameter.
diametrical pertaining to a diameter.
diametrically (Adv.) DIAMETRICAL, pertaining to a diameter.
diedral bounded by two planes, or two plane faces; (noun) a diedral angle.
digonal of symmetry about an axis, such that a half-turn (180) gives the same figure.
digoxin a drug used to improve heart function.
dihedral bounded by two planes, or two plane faces; (noun) a dihedral angle.
dihedron a figure with two sides or surfaces.
dodecagon a plane figure with twelve sides.
dodecagonal like a dodecagon, a plane figure with twelve sides.
dodecahedral relating to a dodecahedron, a twelve-sided solid figure.
dodecahedron (Greek) a twelve-sided solid figure.
ellipsoid a solid, all plane sections of which are ellipses or circles.
endecagon an eleven-sided polygon.
enneagon a polygon with nine sides.
enneagonal belonging to an enneagon; having nine angles.
enneahedral of or like an enneahedron, a nine-sided solid figure.
enneahedron a nine-sided solid figure.
epicycle a circle whose centre moves round the circumference of a larger circle.
epicyclic pertaining to or having the motion of, an epicycle.
epicyclical pertaining to or having the motion of, an epicycle.
equilateral having all sides equal (noun) a shape with all sides equal
equilaterally (Adv.) EQUILATERAL, having all sides equal.
escribe to draw a circle so as to touch one side of a triangle externally; the others (produced) internally.
euclidean related to Euclid, or to the geometry of Euclid.
euclidian related to Euclid, or to the geometry of Euclid.
exsecant a trigonometric function of an angle.
fractal generated by successive subdivisions of a simpler polygon or polyhedron, according to some iterative process; (noun) a fractal shape.
fractality the state of being fractal.
frustum (Lat.) a slice of a solid body; the part of a cone or pyramid between the base and a parallel plane.
generant a thing which generates; spec. in maths a generatrix.
generatrix a line, point or figure that traces out another figure by its motion.
geometrically (Adv.) GEOMETRICAL, related to geometry.
gon a geometrical grade.
haversine half the versed sine of an angle.
hemicycle a half circle; a semicircle.
hendecagon an eleven-sided polygon.
hendecagonal of or like a hendecagon, an eleven-sided polygon.
hendecahedron a solid figure having 11 plane faces.
heptagon a seven-sided plane figure.
heptagonal having seven angles or sides.
heptahedral like a heptahedron.
heptahedron a solid figure having several plane faces.
heptangular having seven angles.
hexagon a six-sided plane figure.
hexagonal having six sides and six angles.
hexagonally (Adv.) HEXAGONAL, having six sides and six angles.
hexagram a figure of six lines, esp a stellate hexagon, aka Star of David.
hexahedral in the form of a hexahedron.
hexahedron a solid body of six sides or faces.
holohedral having all the planes required by complete symmetry, as opposed to hemihedral.
holohedrism the property of having the full number of symmetrically arranged planes crystallographically possible.
holohedron a geometrical form possessing the property of holohedrism.
homaloid a Euclidean space, analogous to a plane.
homaloidal of the nature of a homaloid; flat; plane-shaped.
homoeomorphic of two geometrical figures, such that one can be converted into the other by distortion.
homoeomorphism the state of being homoeomorphic.
hyperboloid a solid figure in which some of the plane sections are hyperbolas.
hyperboloidal of or like a hyperboloid.
hypercube a figure in a space of four or more dimensions having all its sides equal and all its angles right angles.
hyperplane a figure in hyperspace corresponding to a plane in ordinary space.
hyperspace an imagined space having more than three dimensions.
hyperspatial relating to hyperspace, an imagined space having more than three dimensions.
hypotenuse the longest side of a right-angled triangle.
hypothenuse the longest side of a right-angled triangle.
icosahedral of or having the form of an icosahedron.
icosahedron a polyhedron having 20 faces.
icositetrahedra solid figures with twenty-four plane faces.
incenter the centre of an inscribed circle or sphere.
incentre the centre of an inscribed circle or sphere.
interradial between radii or rays.
interradially (Adv.) INTERRADIAL, between radii or rays.
interradius a radius midway between primary radii or perradii.
isogon an equiangular polygon.
isoperimeter a figure with perimeter equal to another.
isoperimetry the state of being isoperimetrical.
isosceles a triangle with two equal sides.
manifolder one who makes manifolds.
nonagon a nine-sided figure.
nonagonal with nine angles.
nonvector something that is not a vector.
obconical conical, but having the apex downward; inversely conical.
octagon an eight-sided plane figure.
octagonal having eight sides and eight angles.
octagonally (Adv.) OCTAGONAL, having eight sides and eight angles.
octahedral having eight faces or sides.
octahedrally (Adv.) OCTAHEDRAL, having eight faces or sides.
octahedron (Greek) a solid bounded by eight plane faces.
octangle an octagon.
octangular having eight angles.
octant the eighth part of circle (45); an angle-measuring instrument with that arc.
octantal relating to an octant, the eighth part of circle (45).
octohedron (Greek) a solid bounded by eight plane faces.
orthocenter the point of intersection of the altitudes of a triangle.
orthocentre the point of intersection of the altitudes of a triangle.
orthogonal at right angles; unrelated or independent of each other.
orthogonality the state of being orthogonal.
orthogonally (Adv.) ORTHOGONAL, right-angled.
paraboloid a surface or solid generated by the rotation of a parabola about its axis.
paraboloidal of or like a paraboloid.
parallelogram a quadrilateral with opposite sides parallel and equal.
parallelopiped a solid figure bounded by six parallelograms, opposite pairs being identical and parallel.
parallelwise in parallel fashion.
pentagon a five-sided plane figure.
pentagonal having five corners or angles (noun) a pentagonal shape
pentagonally (Adv.) PENTAGONAL, having five corners or angles.
pentahedral of or like a pentahedron, a five-sided solid figure.
pentahedron a five-sided solid figure.
perigon (Greek) an angle of 360 degrees.
perimeter the circuit or boundary of any plane figure.
perpendicular at right angles to a line or plane (noun) a perpendicular line
planar relating to a plane, lying in a single plane.
planarity the property of being planar, lying in a single plane.
planate having a flat surface.
polar relating to a pole; (noun) a term in geometry.
polyaxial a shape having many axes or several axis cylinders.
polyaxon having many axes or several axis cylinders; (noun) a figure with many axes.
polyconic pertaining to, or based upon, many cones.
polygon (Greek) a plane figure bounded by straight lines, esp more than four.
polyhedral having many faces or planes.
polyhedric having many faces or planes.
polyhedron a body or solid contained by many sides or planes.
polyomino a flat, many-sided shape made of up of identical squares placed side by side.
porism (Greek) the geometric proposition that it is possible, in certain conditions, for a problem to have any number of solutions.
porismatic relating to a porism, the geometric proposition that it is possible, in certain conditions, for a problem to have any number of solutions.
porismatical relating to a porism, the geometric proposition that it is possible, in certain conditions, for a problem to have any number of solutions.
poristic relating to a porism, the geometric proposition that it is possible, in certain conditions, for a problem to have any number of solutions.
poristical relating to a porism, the geometric proposition that it is possible, in certain conditions, for a problem to have any number of solutions.
prism (Greek) a solid figure of which the two ends are similar, equal, and parallel rectilineal figures, and the sides parallelograms.
prismoid a body that approaches to the form of a prism.
prismoidal having the form of a prismoid.
prismy pertaining to a prism.
pyritohedral of or like a pyritohedron, a pentagonal dodecahedron.
pyritohedron a pentagonal dodecahedron.
quadrant a quarter circumference of circle; an instrument for measuring altitudes.
quadrantal of or pertaining to a quadrant.
quadrature the finding of a square having the same area as some given curvilinear figure.
quadrilateral a polygon of four sides.
quindecagon a geometric figure having fifteen sides and fifteen angles.
rabat (Fr.) to rotate into coincidence with another plane.
rabatment rotation into coincidence with another plane.
rabatte (Fr.) to rotate into coincidence with another plane.
rabatting the act of rabatting.
radiant shining (noun) a straight line from a point about which it is conceived to revolve
radiantly (Adv.) RADIANT, shining.
rectangle a four-sided plane figure with all its angles right angles, esp one with unequal adjacent sides.
rectilineal moving in or forming a straight line.
rectilineally (Adv.) RECTILINEAL, moving in or forming a straight line.
rectilinear moving in or forming a straight line.
rectilinearity the state of being rectilinear.
rectilinearly (Adv.) RECTILINEAR, moving in or forming a straight line.
rhomb an equilateral parallelogram.
rhombic of or like a rhombus, an equilateral parallelogram.
rhombical of or like a rhombus, an equilateral parallelogram.
rhombohedral shaped like a rhombohedron.
rhombohedron a parallelepiped whose faces are rhombuses.
rhomboid a parallelogram with unequal sides.
rhomboidal having, or approaching, the shape of a rhomboid.
rhomboides a rhomboid.
rhomboideus a rhomboid.
rhombus (Lat.) an equilateral parallelogram.
scalene of a triangle, having three unequal sides; (noun) the scalene muscle or scalenus.
scalenohedron a hemihedral form bounded in the hexagonal system by twelve, in the tetragonal by eight, faces, each a scalene triangle.
sech a hyperbolic secant.
sectoral of or pertaining to a sector; as, a sectoral circle.
semiangle the half of a given, or measuring, angle.
semicircle the half of a circle.
semicircled enclosed within a semicircle.
semidiameter half the diameter, esp the angular diameter.
semiperimeter half the perimeter.
simplex (Lat.) a geometrical term, a figure with a minimum number of vertices.
simplicial of or relating to simplexes.
simplicially (Adv.) SIMPLICIAL, of or relating to simplexes.
sinh a hyperbolic function of an angle.
sinical of or pertaining to a sine.
square having four equal sides and four right angles; rigidly conventional (noun) a shape with four equal sides and four right angles; (verb) to make square
squarely (Adv.) SQUARE, having four equal sides and four right angles.
subparallel almost parallel.
subtangent the part of the axis contained between the ordinate and tangent drawn to the same point in a curve.
subtend to be opposite to or to extend under.
subtense a line subtending, or stretching across; a chord; as, the subtense of an arc.
symmetral of symmetry.
tangent a line that touches a curve.
tangental of or pertaining to the nature of a tangent.
tangentally in the direction of a tangent.
tangential of or pertaining to the nature of a tangent.
tanh (Short for) a hyperbolic tangent.
tesseract a figure of a cube within a cube.
tetartohedral having one fourth the number of planes required by complete symmetry.
tetartohedrally (Adv.) TETARTOHEDRAL, having one fourth the number of planes required by complete symmetry.
tetartohedrism the state of being tetartohedral, having one fourth the number of planes required by complete symmetry.
tetragon a plane figure with four angles and four sides.
tetragonal of or pertaining to a tetragon.
tetragonally (Adv.) TETRAGONAL, of or pertaining to a tetragon.
tetrahedral of a solid with four sides.
tetrahedrally (Adv.) TETRAHEDRAL, of a solid with four sides.
tetrahedron a polyhedron that has four faces.
tore a surface described by rotation of conic section about a line.
toroidal like a toroid, shaped like a doughnut or anchor-ring.
toroidally (Adv.) TOROIDAL, like a toroid, shaped like a doughnut or anchor-ring.
tractrix a curve such that the intercept of a tangent by a fixed straight line is constant.
trapezial like a trapezium.
trapeziform in the form of a trapezoid quadrilateral with no sides parallel.
trapezium (Lat.) a quadrilateral with two parallel sides.
trapezoidal in the form of a trapezium.
triangle a polygon having three sides.
triangled having a triangle.
trigon a figure having three angles; a triangle.
trigonal pertaining to or having three angles.
trigonally (Adv.) TRIGONAL, pertaining to or having three angles.
trigonic pertaining to or having three angles.
trigonometric relating to trigonometry.
trigonometrical relating to trigonometry.
trigonometry the study of the properties of triangles and trigonometric functions and of their applications.
trihedral a solid having three sides or faces; thus, a trihedral angle is a solid angle bounded by three plane angles.
trihedron a figure having three sides.
trisoctahedron a solid figure having 24 congruent faces and an octahedron as a base.
tromino a flat, three-sided shape made up of a number of identical squares placed edge to edge.
twistor a complex variable representing spacetime coordinates.
undecagon a polygon having eleven sides.
vectorial of or like a vector.
vectorially (Adv.) VECTORIAL, of or like a vector.
vectorise to make into a vector.
vectorize to make into a vector.
versin a versed sine.
versine a versed sine.
vertex (Lat.) a point, as of an angle or polygon.