# Nouns denoting two and three dimensional shapes

nubble
a small lump or protuberance

a curve or surface whose equation (in Cartesian coordinates) is of the second degree

intersection
a point or set of points common to two or more geometric configurations

vector
a straight line segment whose length is magnitude and whose orientation in space is direction

obtuse triangle
a triangle that contains an obtuse interior angle

sphere
a solid figure bounded by a spherical surface (including the space it encloses)

prism
a polyhedron with two congruent and parallel faces (the bases) and whose lateral faces are parallelograms

cleft
a split or indentation in something (as the palate or chin)

hook
a sharp curve or crook; a shape resembling a hook

sac
an enclosed space

margin
the boundary line or the area immediately inside the boundary

dip
(physics) the angle that a magnetic needle makes with the plane of the horizon

complex plane
a geometric representation of the complex numbers established by the real axis and the orthogonal imaginary axis; it can be thought of as a modified Cartesian plane, with the real part of a complex number represented by a displacement along the x-axis, and the imaginary part by a displacement along the y-axis

parabola
a plane curve formed by the intersection of a right circular cone and a plane parallel to an element of the curve

undulation
an undulating curve

dogleg
angle that resembles the hind leg of a dog

trapezohedron
a polyhedron whose faces are trapeziums

diameter
a straight line connecting the center of a circle with two points on its perimeter (or the center of a sphere with two points on its surface)

angular distance
the angular separation between two objects as perceived by an observer

cylinder
a surface generated by rotating a parallel line around a fixed line