tesseracts

Noun

tesseract (plural tesseracts)

1. 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).
   • Hence the cube determined by these axes is the face of the tesseract which we now have before us.1906, Charles Howard Hinton, The Fourth Dimension, S. Sonnenschein & Company, page 239

   Synonyms:

   four-dimensional hypercube, 4-cube, 8-cell, octachoron, tetracube

2. Any of various fictional mechanisms that explain extradimensional, superluminal, or time travel outside the geometry of the physical universe.
   • "I shall just sit down for a moment and pop on my boots and then I'll be on my way. Speaking of ways, pet, by the way, there is such a thing as a tesseract."1962, Madeleine L'Engle, A Wrinkle in Time, published 2019, unnumbered page