A dielectric material includes a layered metal oxide including a first layer having a positive charge and a second layer having a negative charge, wherein the first layer and the second layer are alternately disposed; a monolayered nanosheet; a nanosheet laminate of the monolayered nanosheets; or a combination thereof, wherein the dielectric material includes a two-dimensional layered material having a two-dimensional crystal structure, wherein the two-dimensional layered material is represented by Chemical Formula 1 X2[A(n−1)MnO(3n+1)]  Chemical Formula 1 wherein, in Chemical Formula 1, X is H, an alkali metal, a cationic polymer, or a combination thereof, A is Ca, Sr, La, Ta, or a combination thereof, M is La, Ta, Ti, or a combination thereof, and n≥1.