• (n.) Conversion of the cell walls into cork tissue by development of suberin; -- commonly taking place in exposed tissues, as when a callus forms over a wound. Suberized cell walls are impervious to water.
Su`ber·i·za'tion noun (Botany) Conversion of the cell walls into cork tissue by development of suberin; -- commonly taking place in exposed tissues, as when a callus forms over a wound. Suberized cell walls are impervious to water. 
the impregnation of cell walls with suberin, causing the formation of cork.