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

Chronic stress weakens the immune system and increases the risk of several conditions including heart disease, anxiety, and depression. —William A. Haseltine, Forbes, 25 Mar. 2025

These treatments are usually tailored to a patient’s immune system, and this specificity can often lead to adverse reactions, according to Dr. Amin Mery of Hill County Allergy and Asthma in Austin. —Cody Copeland, Fort Worth Star-Telegram, 25 Mar. 2025

The immune system sees the pollen as a danger and releases antibodies that attack the allergens. —Janet Loehrke, USA TODAY, 22 Mar. 2025

Cigarette smoking, immune system disorders, rigorous exercise, cancer treatments such as chemotherapy, and surgical removal of the ovaries can all cause vaginal dryness. —Sandra Rose Salathe, Flow Space, 21 Mar. 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