pi·​ne·​al ˈpī-nē-əl How to pronounce pineal (audio) pī-ˈnē- How to pronounce pineal (audio)
: of, relating to, or secreted by the pineal gland
a pineal tumor
the pineal hormone melatonin

Examples of pineal in a Sentence

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,, 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

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'pineal.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

Time Traveler
The first known use of pineal was in 1681

Dictionary Entries Near pineal

Cite this Entry

“Pineal.” Dictionary, Merriam-Webster, Accessed 9 Dec. 2023.

Medical Definition


1 of 2 adjective
pi·​ne·​al ˈpī-nē-əl How to pronounce pineal (audio) pī-ˈ How to pronounce pineal (audio)
: of, relating to, or being the pineal gland


2 of 2 noun
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