Carburizing is a term used in materials science and engineering to describe the process of adding carbon to a material to increase its hardness and surface strength. Synonyms for carburizing include carbonizing, case hardening, surface hardening, and gas carburizing. These terms all refer to the process of introducing carbon to the surface of a material, typically through exposure to a carbon-rich gas or atmosphere. Other related terms include nitriding (adding nitrogen to a material), boronizing (adding boron), and chromizing (adding chromium), all of which can also be used to improve the properties of materials for various applications.