noun, plural thy·mus·es, thy·mi [thahy-mahy] /ˈθaɪ maɪ/. Anatomy.
- a ductless, butterfly-shaped gland lying at the base of the neck, formed mostly of lymphatic tissue and aiding in the production of T cells of the immune system: after puberty, the lymphatic tissue gradually degenerates.
noun plural -muses or -mi (-maɪ)
- a glandular organ of vertebrates, consisting in man of two lobes situated below the thyroid. In early life it produces lymphocytes and is thought to influence certain immunological responses. It atrophies with age and is almost nonexistent in the adult
n.gland near the base of the neck, 1690s, Modern Latin, from Greek thymos “a warty excrescence,” used of the gland by Galen, literally “thyme,” probably so called because of a fancied resemblance to a bunch of thyme (see thyme). n. pl. thy•mus•es
- A lymphoid organ that is located in the superior mediastinum and lower part of the neck and is necessary in early life for the normal development of immunological function.
- The thymus of a calf or lamb.
- An organ of the lymphatic system located behind the upper sternum (breastbone). T cells (T lymphocytes) develop and mature in the thymus before entering the circulation. In humans, the thymus stops growing in early childhood and gradually shrinks in size through adulthood, resulting in a gradual decline in immune system function.
A gland located behind the breastbone that functions in the development of the immune system. The thymus is large in infancy and early childhood but begins to atrophy between ages eight and ten.