Symbols:Abbreviations/R/Reduced Echelon Form

Abbreviation: ref or rref

ref is an abbreviation for reduced echelon form.

rref is an abbreviation for reduced row echelon form.

The matrix $\mathbf A$ is in reduced echelon form if and only if, in addition to being in echelon form, the leading $1$ in any non-zero row is the only non-zero element in the column in which that $1$ occurs.

Such a matrix is called a reduced echelon matrix.