pituitary gland

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A small oval endocrine gland attached to the base of the vertebrate brain and consisting of an anterior and a posterior lobe, the secretions of which control the other endocrine glands and influence growth, metabolism, and maturation.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun anatomy An endocrine gland, about the size of a pea, that sits in a small, bony cavity at the base of the brain whose secretions control the other endocrine glands and influence growth, metabolism, and maturation.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the master gland of the endocrine system; located at the base of the brain