thymus

 
Pronunciation: /ˈθʌɪməs/
(also thymus gland)

noun (plural thymi /-mʌɪ/)

  • a lymphoid organ situated in the neck of vertebrates which produces T-lymphocytes for the immune system. The human thymus becomes much smaller at the approach of puberty.

Origin:

late 16th century (denoting a growth or tumour resembling a bud): from Greek thumos 'excrescence like a thyme bud, thymus gland'