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

The researchers now plan to expand on their findings, looking at the long-term effects of high fructose consumption on the immune system. —New Atlas, 27 June 2025

Antigens are the molecules in vaccines that trigger a response from the immune system, training it to identify the specific pathogen. —Jake Scott, The Conversation, 26 June 2025

Today, children under age 2 get vaccines against 15 diseases—but those vaccines target just 180 antigens, asking much less of the immune system. —ArsTechnica, 25 June 2025

In turn, the mast cells release their torrent of chemical signals, setting off a cascade of immune system processes. —Kate Raphael, Discover Magazine, 23 June 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