Thalamus \Thal"a*mus\, n.; pl. Thalami. [L. thalamus chamber, Gr. qa`lamos.]

1. (Anat.) A mass of nervous matter on either side of the third ventricle of the brain; -- called also optic thalamus.

2. (Bot.)
   (a) Same as Thallus.
   (b) The receptacle of a flower; a torus.

Source: Webster's Revised Unabridged Dictionary (1913)