pituitary (adj.)

1610s, from Latin pituitarius "mucous," from pituita "clammy moisture, phlegm, mucus, slime," possibly from a suffixed form of PIE root *peie- "to be fat, swell" (see fat (adj.)). Taken as the name for the gland because it was believed that it channeled mucus to the nose. As a noun by 1899.