Density functional theory (DFT) is a widely used computational method in physics, chemistry, and materials science. However, it has several synonyms that may be used interchangeably. Some of these include Kohn-Sham theory, electronic density functional theory, and orbital-free density functional theory. Kohn-Sham theory is named after the scientists who developed it, Walter Kohn and Lu Sham, while electronic density functional theory emphasizes the use of electronic density as the basic variable. Orbital-free density functional theory, on the other hand, does not rely on orbitals to describe the electron density. Regardless of the name used, DFT provides a powerful tool to study electronic structures and properties of materials in an efficient and accurate manner.