The Collaborative International Dictionary of English v.0.48:

Pituitary \Pi*tu"i*ta*ry\, a. [L. pituita phlegm, pituite: cf.
   F. pituitarie.] (Anat.)
   (a) Secreting mucus or phlegm; as, the pituitary membrane, or
       the mucous membrane which lines the nasal cavities.
   (b) Of or pertaining to the pituitary body; as, the pituitary
       fossa.
       [1913 Webster]

   Pituitary body or Pituitary gland (Anat.), a a small,
      somewhat cherry-shaped endocrine gland, situated in the
      pituitary fossa, and suspended from the base of the
      hypothalamus; the hypophysis; -- called also glandula
      pituitaria, and basilaris. It secretes th pituitary
      hormones: oxytocin; vasopresin; antidiuretic hormone;
      luteinizing hormone; somatotropins; prolactin; thyroid
      stimulating hormone; gonadotropins; adrenal corticotropin
      and other peptide hormones. It affects all hormonal
      functions, and is thus called the "master gland".

   Pituitary fossa (Anat.), the ephippium.
      [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

pituitary gland
    n 1: the master gland of the endocrine system; located at the
         base of the brain [syn: pituitary, pituitary gland,
         pituitary body, hypophysis]