1. Either of a pair of egg-shaped masses of gray matter lying beneath each cerebral hemisphere in the brain that relay sensory information to the cerebral cortex.

They are concerned with awareness of all the main senses except for smell.

2. Either of two large, ovoid masses, consisting chiefly of grey substance, situated one on each side of and forming part of the lateral wall of the third ventricle.

It is divided into two major parts: dorsal and ventral, each of which contains many nuclei.