"unit cell." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/unit-cell>.
unit cell. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/unit-cell
The smallest building block of a crystal, consisting of atoms, ions, or molecules, whose geometric arrangement defines a crystal's characteristic symmetry and whose repetition in space produces a crystal lattice.