A ductless gland, consisting mainly of lymphatic tissue, located behind the top of the breastbone. It is most active during puberty, after which it shrinks in size. It plays an important role in the development of the immune system and produces lymphocytes.
User Defined Definitions
"large genus of Old World mints: thyme"
"a ductless glandular organ at the base of the neck that produces lymphocytes and aids in producing immunity; atrophies with age"