What does "tesseract" mean?

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).

How do you pronounce "tesseract"?

Pronounced //ˈte-sə-ˌrakt//.

Common synonyms include: 4-cube, 8 cell, 8-cell, four dimensional, four-dimensional hypercube, hypercube.

//ˈte-sə-ˌrakt// noun

noun ·Uncommon ·Advanced level

Noun

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."
2
the four-dimensional analogue of a cube wordnet
3
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.""