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  • EO
    EO
    executive order.
  • eo-
    eo-
    a combining form meaning “early,” “primeval,” used in the formation of compound words.
  • e.o.
    e.o.
    abbreviation
    ex officio.

EO

1 American  
  1. executive order.


eo- 2 American  
  1. a combining form meaning “early,” “primeval,” used in the formation of compound words.

    Eocene; eohippus.


e.o. 3 American  

abbreviation

  1. ex officio.


e.o. 1 British  

abbreviation

  1. ex officio

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

eo- 2 British  

combining form

  1. early or primeval

    Eocene

    eohippus

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of eo-

< Greek, combining form of ēṓs ( Attic héōs ) dawn; akin to east, Aurora


Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

District Judge Indira Talwani issued an injunction that prevented the federal government from implementing that EO.

From Slate ● Aug. 20, 2026

Larry Ottaviano, vice president of sales for surveillance-camera company PVP Advanced EO Systems, said he has never seen an increase in demand like this year.

From The Wall Street Journal ● May 8, 2026

“We see the signing of this EO as a substantial step towards diminishing regulatory risk in this emerging class of therapies, enabling investor comfort,” RBC Capital Markets analyst Brian Abrahams told investors.

From MarketWatch ● Apr. 20, 2026

EO: Most of the time, I document it for myself.

From Los Angeles Times ● Sep. 10, 2025

"Even super-low EO? We might be able to—" "Loss of signal, Flight."

From "The Martian" by Andy Weir

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