The Collaborative International Dictionary of English v.0.48:
telencephalon \telencephalon\ n. 1. the anterior division of the forebrain; the cerebrum and related parts of the hypothalamus. [WordNet 1.5]WordNet (r) 3.0 (2006):
telencephalon n 1: the anterior division of the forebrain; the cerebrum and related parts of the hypothalamus