En-cĕph'a-lŏn or En-cĕph'a-lŏs, n.

n. [Gr. ἐγκέφαλος, within the head, from ἐν, in, and κεφαλή, head.] That which is within the head; hence, the brain.

In man the encephalos reaches its full size about seven years of age. Sir W. Hamilton.