thymus

noun

thy·​mus ˈthī-məs 

variants or thymus gland

plural thymuses also thymi ˈthī-ˌmī 

: a glandular structure of largely lymphoid tissue that functions especially in cell-mediated immunity by being the site where T cells develop, is present in the young of most vertebrates typically in the upper anterior chest or at the base of the neck, and gradually decreases in size and activity after puberty

Example Sentences

Recent Examples on the Web

With enough time, our body’s defenses against viral infections (B cells) stay out of the way in our ‘memory banks’ – lying dormant in lymph nodes, thymus and bone marrow – until they’re needed to attack a virus. —Theresa Sullivan Barger, Discover Magazine, 26 Dec. 2022

For example, Yale University researchers found restricting calories increased the health of the thymus, an organ that produces immune system T cells — one of the body’s key warriors against invaders. —Sandee Lamotte, CNN, 10 Feb. 2023

While scouring the scientific literature for a molecular signature of age present in blood, Kayser and his team realized that the organ that pumps out T cells, the thymus, is gradually replaced with fat tissue as people age. —Eliza Strickland, Discover Magazine, 23 Nov. 2010

In November, 2014, Carl Evans, a seventy-seven-year-old former janitor from Orange County, took a fall and, when hospitalized, was tentatively diagnosed as having end-stage thymus cancer. —Ava Kofman, The New Yorker, 28 Nov. 2022

For example, the root chakra correlates with the testes or ovaries, the throat chakra with the thyroid gland and the heart chakra with the thymus. —Sara Novak, Discover Magazine, 1 Dec. 2021

The thymus gland and the bone marrow are two examples of immune-cell-producing organs. —Amber Smith, Discover Magazine, 17 Oct. 2022

In November 2014, Carl Evans, a 77-year-old former janitor from Orange County, took a fall and, when hospitalized, was tentatively diagnosed as having end-stage thymus cancer. —Ava Kofman, ProPublica, 28 Nov. 2022

Easton’s other condition prevented his thymus from functioning properly. —NBC News, 8 Mar. 2022

See More

Word History

Etymology

New Latin, from Greek thymos warty excrescence, thymus

First Known Use

1578, in the meaning defined above

Phrases Containing thymus

• thymus gland

• thymus gland

Kids Definition

thymus

noun

thy·​mus ˈthī-məs 

plural thymuses also thymi -ˌmī 

: a gland that is found in the young of most vertebrates usually in the chest near the heart, that before and for a time after birth has very important effects on the production and development of T cells, and that becomes less active and gradually shrinks or disappears with age

Medical Definition

thymus

noun

thy·​mus ˈthī-məs 

variants or thymus gland

plural thymuses also thymi -ˌmī 

: a glandular structure of largely lymphoid tissue that functions in cell-mediated immunity by being the site where T cells develop, that is present in the young of most vertebrates typically in the upper anterior chest or at the base of the neck, that arises from the epithelium of one or more embryonic branchial clefts, and that gradually decreases in size and activity after puberty