Thymus \Thy"mus\, a. [NL., fr. Gr. qy`mos.]

(Anat.) Of, pertaining to, or designating, the thymus gland. -- n. The thymus gland.

Thymus gland, or Thymus body, a ductless gland in the throat, or in the neighboring region, of nearly all vertebrates. In man and other mammals it is the throat, or neck, sweetbread, which lies in the upper part of the thorax and lower part of the throat. It is largest in fetal and early life, and disappears or becomes rudimentary in the adult.

Source: Webster's Revised Unabridged Dictionary (1913)