pentachoron

noun

1. A four-dimensional object analogous to a tetrahedron, constructed out of five tetrahedra.

   “A triangle becomes a tetrahedron (a type of pyramid), then a pentachoron (a hyperpyramid).”

   “Geometrically, K₃ relates to a triangle, K₄ a tetrahedron, K₅ a pentachoron, etc.”

   “The tetrahedron is a 3-simplex whose 4-simplex analog is the pentachoron, a four-dimensional body which can be orphographically ^([sic]) projected onto a quincrux (as well as a pentagram and other shapes).”