in geometry, biology, mineralogy, and solid state physics, a primitive cell is a minimum-volume cell (a unit cell) corresponding to a single lattice point of a structure with discrete translational symmetry. the concept is used particularly in describing crystal structure in two and three dimensions, though it makes sense in all dimensions. a lattice can be characterized by the geometry of its primitive cell.
the primitive cell is a primitive place. a primitive unit is a section of the tiling (usually a parallelogram or a set of neighboring tiles) that generates the whole tiling using only translations, and is as small as possible.
the primitive cell is a fundamental domain with respect to translational symmetry only. in the case of additional symmetries a fundamental domain is smaller.