immune system

noun

: the bodily system that protects the body from foreign substances, cells, and tissues by producing the immune response and that includes especially the thymus, spleen, lymph nodes, special deposits of lymphoid tissue (as in the gastrointestinal tract and bone marrow), macrophages, lymphocytes including the B cells and T cells, and antibodies

Examples of immune system in a Sentence

Recent Examples on the Web

Other risk factors for strep throat include infrequent handwashing, a weakened immune system, and seasonal changes. —Brandi Jones, Msn-Ed, Health, 26 Dec. 2024

The same is true for younger children, people with a chronic medical condition and anyone else who may have a weaker immune system. —Bruce Y. Lee, Forbes, 26 Dec. 2024

Threat level: Infants under 1, whose immune systems are still developing, are at greatest risk for serious disease and death from whooping cough. —Avery Lotz, Axios, 24 Dec. 2024

People who have a weakened immune system, conditions like diabetes or use steroids for other medical issues are most at risk for fungal eye infections. —Josh Hammer, Newsweek, 23 Dec. 2024

Word History

First Known Use

circa 1919, in the meaning defined above

Kids Definition

immune system

noun

: the bodily system that protects the body from foreign substances, cells, and tissues by producing the immune response and that includes especially the thymus, spleen, lymph nodes, lymphocytes, and antibodies

Medical Definition

immune system

noun

: the bodily system that protects the body from foreign substances, cells, and tissues by producing the immune response and that includes especially the thymus, spleen, lymph nodes, special deposits of lymphoid tissue (as in the gastrointestinal tract and bone marrow), lymphocytes including the B cells and T cells, and antibodies