thymus

The thymus is a small, two-lobed gland in the upper chest, located behind the breastbone. It is part of the immune system and plays a central role in the development of T lymphocytes, the immune cells responsible for recognizing and responding to specific pathogens and abnormal cells. The thymus is especially active during childhood, when it provides a structured environment for T cells to mature. After puberty, it gradually shrinks and becomes less prominent, although it continues to perform immune functions throughout life. In medicine, the term thymus is used when discussing conditions affecting the gland, including enlargement, inflammation, tumors, and congenital abnormalities. It also appears in the names of related structures and procedures, such as the thymus gland and thymectomy. Although unfamiliar to many readers, the thymus is a useful word to know because it identifies a small organ with an important role in shaping the body's immune defenses.

A small, two-lobed gland situated behind the breastbone in the upper chest. It is a primary lymphoid organ involved in the maturation of T lymphocytes and is most active in childhood, gradually shrinking after puberty.

Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.

Etymology of thymus

The English anatomical term comes through modern Latin from Ancient Greek θύμος (thúmos), meaning “thymus gland.” Medical terms such as thymocyte, thymoma, and thymectomy were developed from the same Greek base and are now common in biology and medicine.

Related word forms

How thymus is actually used

This is primarily a medical and anatomical term. It is usually singular when referring to the organ in a particular person or animal, and plural forms often appear in comparative or developmental contexts.

Easily confused with thymus

Words and phrases paired with thymus