The lattice constant, or lattice parameter, refers to the physical dimension of unit cells during a space lattice. Lattices in three dimensions generally have three lattice constants, mentioned as a, b, and c. However, within the special case of cubic crystal structures, all of the constants are equal and are mentioned as a. Similarly, in hexagonal crystal structures, the a and b constants are equal, and that we only ask the a and c constants. a gaggle of lattice constants might be mentioned as lattice parameters. However, the complete set of lattice parameters contains the three lattice constants and therefore the three angles between them.