By referring collectively to e1, e2, e3 as the "e" basis and to n1, n2, n3 as the "n" basis, the matrix containing all the "c""jk" is known as the "transformation matrix from "e" to "n"", or the "rotation matrix from "e" to "n"" (because it can be imagined as the "rotation" of a vector from one basis to another), or the "direction cosine matrix from "e" to "n"" (because it contains direction cosines). The properties of a rotation matrix are such that its inverse is equal to its transpose. This means that the "rotation matrix from "e" to "n"" is the transpose of "rotation matrix from "n" to "e"".