Sciency Words: Ylem (An A to Z Challenge Post)

Today’s post is a special A to Z Challenge edition of Sciency Words, an ongoing series here on Planet Pailly where we take a look at some interesting science or science related term so we can all expand our scientific vocabularies together. In today’s post, Y is for:


When George Gamow and Ralph Alpher were developing the Big Bang Theory (the actual theory, not the T.V. show), they needed a term for the bizarre form of matter they predicted would have existed in the early universe. They ended up picking the awkward-sounding word ylem.

In a 1968 interview, Gamow had this to say about the word’s origins: “You can look in the Webster dictionary. This is a word—I think it’s an old Hebrew word, but Aristotle was using it—in Webster dictionary (sic) is says ‘material from which elements were formed.’”

As a word nerd, I’m compelled to make two points of clarification before we can move on. First, I hate when people cite “Webster’s dictionary” as a source. Webster is not a trademarked name (Merriam-Webster is), so anybody can stick “Webster” on a dictionary and make it sound authoritative. Second, ylem does not come from Hebrew; the etymology traces back to the Greek word for matter (this according to my favorite real dictionary, The New American Heritage Dictionary, Fifth Edition).

Okay, word nerd rant over.

Aristotle did have something to say about the “fundamental matter” from which the elements formed. By elements, of course, he meant earth, fire, wind, and water. Aristotle’s term for this was proto-hyle. Over the millennia since Aristotle’s time, the hyle part of proto-hyle changed phonetically (Latin added an m, French dropped the h), and thus ylem entered English as a philosophy term.

Gamow and Alpher then turned it into a scientific term. Regardless of which dictionary they were looking at, for them it meant the primordial matter that existed after the Big Bang but before the chemical elements formed.

In a sense, this isn’t too far from the proto-hyle Aristotle was talking about. Except by elements, Gamow and Alpher meant things like hydrogen and helium, not earth or fire. Also, they could be a whole lot more specific about what ylem actually was: a highly charged plasma of protons, neutrons, and electrons that took roughly 400,000 years to cool off before it could start combining as atoms.

Next time on Sciency Words: A to Z, animals may not be able to talk, but they have other ways to communicate with us.

10 thoughts on “Sciency Words: Ylem (An A to Z Challenge Post)

  1. Are you implying suh, that Merriam-Webster is not a *real* dictionary 😡

    Actually, kinda cool to find out about another one. When I google “New American Heritage”, I get a couple of different sites claiming to be the “American Heritage” dictionary, although I’m guessing the Houghton Mifflin Harcourt site is the real one.

    Liked by 1 person

    1. Not at all. Merriam-Webster is a fine dictionary and the proper successor to Noah Webster’s work. Webster’s dictionaries (without the Merriam) are taking advantage of a lapsed trademark to capitalize on Merriam-Webster’s good reputation.

      As a matter of personal preference, the New American Heritage Dictionary (you guessed right, it’s the Houghton Mifflin Harcourt one… didn’t know there were others) is my dictionary of choice. I like reading the opinions of their “usage panel” to get a sense of how the language is currently evolving.

      Or at least, how it was evolving as of 2011. As soon as there’s a sixth edition, I’ll be buying it to get the updated usage opinions.

      Liked by 1 person

      1. On Merriam-Webster, thanks! Hopefully you picked up that my first sentence above was tongue-in-cheek.

        I saw the usage panel mentioned when I visited the AHDictionary site, but couldn’t find the panel itself. Is it something only available to paying members?

        Liked by 1 person

      2. Yeah, I picked it up. No worries!

        I guess being a member would let you see the usage panel stuff. I have a physical copy, so I don’t really know much about how their membership stuff works.

        Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.