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

After removal, the T-cells are genetically modified to recognize a specific protein within cancer cells and infused back into the patient’s immune system to search and destroy the diseased cells. —Cindy Krischer Goodman, Sun Sentinel, 14 May 2025

Other key nutrients support bone health, brain function, heart health, and the immune system. —Cristina Mutchler, Verywell Health, 14 May 2025

Balachandran has used mRNA technology to create personalized vaccines that research has indicated could boost patients’ immune systems to help treat pancreatic cancer. —Chantelle Lee, Time, 14 May 2025

For decades scientists have been puzzled by a tiny parasite that affects millions worldwide, with the power to liquefy human organs and evade the immune system in ways that science hasn't been able to explain. —Maria Azzurra Volpe, MSNBC Newsweek, 13 May 2025

Word History

First Known Use

circa 1919, in the meaning defined above

Rhymes for immune system

• cryptosystem
• ecosystem
• intersystem
• multisystem
• photosystem
• subsystem

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