In geometry, a cell is a three-dimensional element that is part of a higher-dimensional object.
For example, a cubic honeycomb is made of cubic cells, with 4 cubes on each edge. A tesseract is also made of cubic cells, but only has 3 cubes on each edge.
Regular convex polychora are sometimes named by how many cells they contain, just like n-gon and n-hedron are used as a shorthand for polygonal and polyhedral names. For example, the tesseract can also be called an octachoron or an 8-cell because it contains 8 cubic cells.