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

Who is at risk for consuming unpasteurized apple cider? Children, older adults, pregnant women and people with weakened immune systems are more susceptible to the effects of food poisoning. —Katie Wiseman, The Indianapolis Star, 4 Oct. 2024

Those most at risk of contracting a foodborne illness are pregnant women, infants and young children, older adults and people with weakened immune systems. —Olivia Rose, The Arizona Republic, 4 Oct. 2024

Regular sunlight will boost your body’s production of vitamin D, which is crucial for immune system function. —Peter Stewart, Forbes, 2 Oct. 2024

People with this condition have immune systems that attack their hair follicles. —Corey Whelan, Verywell Health, 2 Oct. 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