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
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Provides Immune System Support Sunflower seeds contain minerals and nutrients like zinc and selenium that help your body's natural ability to defend against viruses and bacteria and provide other immune system benefits.67 5. Cristina Mutchler, Verywell Health, 23 May 2025 Read More: What Is Regeneration and Can Other Organs Regenerate Like the Liver? Insulin, Made in the Spleen In this study, researchers set their sights on type 1 diabetes, a condition in which the immune system destroys insulin-producing pancreatic islet cells. Discover Magazine, 23 May 2025 Salmonella is an organism which can cause serious and fatal infections in children, the elderly, and other people with weakened immune systems, according to the CDC. Natalie Neysa Alund, USA Today, 21 May 2025 Even at low levels, PFAS have been linked to cancer, reproductive harm, immune system damage and other serious health problems. Chloe Sorvino, Forbes.com, 21 May 2025 See All Example Sentences for immune system

Word History

First Known Use

circa 1919, in the meaning defined above

Time Traveler
The first known use of immune system was circa 1919

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Cite this Entry

“Immune system.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/immune%20system. Accessed 5 Jun. 2025.

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

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