#diagonal  (mathematics) a set of entries in a square matrix running diagonally either from the upper left to lower right entry or running from the upper right to lower left entry
  supertype:  set  (mathematics) an abstract collection of numbers or symbols; "the set of prime numbers is infinite"
  part of:  square_matrix  a matrix with the same number of rows and columns

No statement uses or specializes diagonal; click here to add one.