The Collaborative International Dictionary
Thalamencephalon
Thalamencephalon \Thal`a*men*ceph"a*lon\, n. [NL. See Thalamus, and Encephalon.] (Anat.) The segment of the brain next in front of the midbrain, including the thalami, pineal gland, and pituitary body; the diencephalon; the interbrain.
Wiktionary
thalamencephalon
n. (context archaic anatomy English) The segment of the brain next in front of the midbrain, including the thalamus, pineal gland, and pituitary body.