pineal
adjective
pi·ne·al ˈpī-nē-əl 
pī-ˈnē-
pī-ˈnē- : of, relating to, or secreted by the pineal gland
a pineal tumor
the pineal hormone melatonin
Example Sentences
Recent Examples on the Web And teenagers whose pineal glands haven't yet calcified can actually travel to another time period and get stuck there, which Steve realizes is what has happened to Brianna. 
Jennifer Ouellette, Ars Technica, 22 Nov. 2020 This video shows a monitor lizard skull fossil fragment with both the parietal and pineal foramina visible (highlighted in yellow). Amina Khan, latimes.com, 3 Apr. 2018 What purpose the fourth eye served in addition to pineal eye is hard to say. David Grossman, Popular Mechanics, 2 Apr. 2018
Jennifer Ouellette, Ars Technica, 22 Nov. 2020 This video shows a monitor lizard skull fossil fragment with both the parietal and pineal foramina visible (highlighted in yellow). Amina Khan, latimes.com, 3 Apr. 2018 What purpose the fourth eye served in addition to pineal eye is hard to say. David Grossman, Popular Mechanics, 2 Apr. 2018 Word History
Etymology
French pinéal, from Middle French, from Latin pinea pine cone, from feminine of pineus of pine, from pinus
First Known Use
1681, in the meaning defined above
Phrases Containing pineal
Medical Definition
pineal 1 of 2
adjective
pi·ne·al ˈpī-nē-əl pī-ˈ
pī-ˈ : of, relating to, or being the pineal gland
pineal
2 of 2noun
: pineal gland