a. [ Gr. 'a priv. + &unr_; nuptial bed. ] (Bot.) Not furnished with shields or beds for the spores, as the thallus of certain lichens. [ 1913 Webster ]
‖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. [ 1913 Webster ]
2. (Bot.) (a) Same as Thallus. (b) The receptacle of a flower; a torus. [ 1913 Webster ]