thymus
/ˈθaɪməs/
noun
- A small organ in the upper chest, behind the breastbone, that is part of the immune system and helps produce T-cells, especially in children.
- The thymus is most active during childhood and shrinks as we get older.
- An infection can sometimes cause the thymus to become enlarged.
- Scientists have discovered that the thymus plays a vital role in training immune cells.