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

Infants, older adults, and people with weakened immune systems are more vulnerable to complications and should seek prompt care if symptoms worsen. —Abby Norman, Verywell Health, 2 Dec. 2024

Listeria is a foodborne bacterial illness, that can cause listeriosis, which primarily affects older adults, people with weakened immune systems, pregnant women and newborns. —Greta Cross, USA TODAY, 2 Dec. 2024

Salmonella can be especially dangerous to young children, elderly people, or those with weakened immune systems. —Abigail Wilt, Southern Living, 2 Dec. 2024

Salmonella can cause fatal infections in young children, elderly people or other individuals with weakened immune systems. —Megan Cerullo, CBS News, 28 Nov. 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