Vaccinate is a term used to describe the process of introducing a vaccine into the body to protect against a particular disease. INOCULATE and IMMUNIZE are two terms that are often used interchangeably with vaccinate, although they have slightly different meanings. INOCULATE refers to introducing a weakened form of a virus or bacteria into the body to stimulate an immune response, while IMMUNIZE refers to the process of making someone resistant to a particular disease by introducing antibodies or other substances.