pineal gland
small endocrine gland found in most vertebrates, which produces melatonin; in humans, located in the epithalamus, in a groove where the two halves of the thalamus join; its shape and size resembles a pine nut, after which it is named
en-US/ˌpaɪˈniəl ˈɡlænd/
en-GB/ˈpɪnɪəl ˈɡlænd/