Reduced Row Echelon Form (RREF) is a specific type of matrix arrangement used in linear algebra. A matrix is in RREF if it meets three criteria: each leading entry (the first non-zero number from the left in a row) is 1, each leading 1 is the only non-zero entry in its column, and the leading 1s move to the right as you move down the rows. RREF is useful for solving systems of linear equations, as it simplifies the matrix to make the solutions more apparent. By transforming a matrix into RREF using Gaussian elimination or Gauss-Jordan elimination, one can easily identify the values of the variables involved.