(mathematics) A matrix having the same number of rows as columns.

(linear algebra) An identity matrix

(linear algebra, probability theory, statistics) A matrix having the property that the entries in each column are non-negative, real and sum to 1.

(linear algebra) Of a matrix A, another matrix B such that A multiplied by B and B multiplied by A both equal the identity matrix.

(linear algebra) A diagonal matrix all of the diagonal elements of which are equal to 1.

(linear algebra) A matrix in which the entries outside the main diagonal are all zero.

Together with lauds, the earliest of the canonical hours; normally at sunrise, but often earlier. / Morning prayers.

plural of matin

(cricket) an administrative official who decides on any penalties for bad conduct etc

(transitive) To enroll as a member of a body, especially of a college or university / (intransitive) To be enrolled as a member of a body, especially of a college or university.