sphere
round, rotationally symmetric shape of the 2D surface of a ball in 3D space
celestial sphere
imaginary sphere of arbitrarily large radius, concentric with the observer
Riemann sphere
model of the extended complex plane plus a point at infinity
circumscribed sphere
sphere that contains a polyhedron and touches each of the vertices thereof
Steeple ball
closed capsule on the finial of many buildings in the German-speaking countries
radome
"Radar dome"; weatherproof structures enclosing radar antennas
wooden bullet
less-lethal projectile
inscribed sphere
sphere contained within a polyhedron, tangent to each of its faces
unit sphere
set of points in 3D space of distance 1 from a fixed central point
puzzle globe
spherical assembly of puzzle pieces
osculating sphere
sphere that approximates a curve at one point