In typesetting, a matrix (often abbreviated to "mat") is a mold for casting the letters known as sorts used in letterpress printing. A matrice is inserted into the bottom of a hand mould, the hand mould is locked and molten type metal is poured into a straight-sided vertical cavity above the matrice. When the metal has cooled and solidified the mould is unlocked and a newly-cast metal sort is removed.

Матрица в издательском деле