Transpose

Matrix operation which flips a matrix over its diagonal

In linear algebra, transposition is an operation that flips a matrix over its diagonal; that is, transposition switches the row and column indices of the matrix A to produce another matrix, called the transpose of A and often denoted AT (among other notations). The transpose of a matrix was introduced in 1858 by the British mathematician Arthur Cayley.

From Wikipedia, under CC BY-SA. More on occurri.