The Indo-European root *aus- ‘to shine’ gave rise not only to English east and Easter and Latin aurora, but also to Greek eos ‘dawn.’ From that comes the eo- that appears as a first element in several learned coinages, where it means ‘dawn’ in the figurative sense of ‘earliest, most primitive.’ One such coinage is eohippus, or ‘dawn horse,’ a name given to the earliest distinguishable ancestor of the modern horse. The eohippus (for which Spanish has the additional form eohipo) was originally the size of a dog; it developed in the Americas and ultimately died out there, but not before its larger descendants had colonized other continents, from which they were reintroduced into the Americas beginning at the end of the 1400s.

Another eo- word, one whose second element comes from Greek kainos ‘recent,’ is Eoceno/Eocene, which the 1911 Encyclopedia Britannica identified this way: “in geology, the name suggested by Sir C. Lyell in 1833 for the lower subdivision of the rocks of the Tertiary Era. The term was intended to convey the idea that this was the period which saw the dawn of the recent or existing forms of life, because it was estimated that among the fossils of this period only 31% (roughly a third) of the species are still living. Since Lyell’s time much has been learned about the fauna and flora of the period, and many palaeontologists doubt if any of the Eocene species are still extant, unless it be some of the lowest forms of life. Nevertheless the name is a convenient one and is in general use. The Eocene as originally defined, however, was not long left intact, for E. Beyrich in 1854 proposed the term ‘Oligocene’ for the upper portion, and later, in 1874, K. Schimper suggested ‘Paleocene’ as a separate appellation for the lower portion. The Oligocene division has been generally accepted as a distinct period, but ‘Paleocene’ is not so widely used.”

Today’s dictionaries show Eoceno/Eocene referring to ‘the second epoch of the Tertiary Period.’ (It’s as if scientists instituted something akin to a permanent Daylight Saving Time for the Eocene, bumping it up one level.)

Users of Canon single-lens reflex (SLR) digital cameras may wonder if EOS, the designation for those models, was taken from Greek eos, but the name arose as an English-language acronym for ‘Electro-Optical System.’ As a recent afterthought, however, Canon took advantage of the Greek word’s meaning and reinterpreted EOS as ‘Goddess of the Dawn’ in its online Canon Camera Museum.

© 2015 Steven Schwartzman


9 Comments (+add yours?)

  1. Frederick Jackson
    Sep 26, 2015 @ 17:30:16

    And the relationship of eos to deus, dios etc.? I dare not opine as my alter ego is “Isidore of Seville”


  2. shoreacres
    Sep 27, 2015 @ 22:44:08

    Those geologists are as bad about recategorizing as botanists. Not that recategorizing is bad, especially in light of new knowledge, but it certainly does get confusing. At least I have these geologic periods sorted now, and I laughed at your permanent Daylight Saving Time analogy for the Eocene.

    I very nearly fell into the trap of thinking eon belonged here, but now I know that’s not so. The root is different: *aiw, which led to “vital force, life, long life, eternity.”

    But here’s a question. The OED labels *aiw as PIE, but you referred to *aus as Indo-European. I don’t see any difference in the form of the roots. And, I’ve seen PIE rendered as Proto Indo-European, but in your glossary you refer to Primitive Indo-European. Is this just a terminology issue? If not, how do you tell the difference between PIE and Indo-European?

    I guess that’s two questions.

    Here’s a third. Do Canon users pronounce EOS as a word? a true acronym? I would have called it an initialism, because I pronounce the letters separately. Now that I have one, I need to know how all the cool kids do it.


    • Steve Schwartzman
      Sep 28, 2015 @ 01:51:22

      I have to admit I thought of permanent Daylight Saving Time as a clever way to put it.

      Some sources use Primitive Indo-European or Proto Indo-European (PIE) to refer to the prehistoric ancestor of the current languages, which are Indo-European. Other sources say just Indo-European for both, relying on context to distinguish the meaning. For example, the last word in the frequent phrase Indo-European root is an overt indication that the prehistoric ancestor is meant.

      Your last question is one that I hadn’t thought about. I’ve always mentally pronounced EOS as ee-ohss, but I don’t believe I’ve heard anyone say the term out loud. I looked online just now and found this in Wikipedia: “The acronym ‘EOS’ was chosen for Eos, the Titan goddess of the dawn in Greek mythology, and is often pronounced as a word (UK /ˈiː.ɒs/ or US /ˈiː.ɑːs/), although some spell out the letters, reading it as an initialism.” It seems cool kids can go either way.


  3. Maria F.
    Oct 03, 2015 @ 16:44:28

    I did read about the modern horse colonising the New World, but I wonder about the Mayan culture with the 5000-year old language called “Proto-Mayan”. How clever of Canon to bring the EOS to life!


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©2011–2016 Steven Schwartzman
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