The Dilemma: You're reading a document that's riddled with needless, pretentious Latin abbreviations (a legal brief, e.g., or mental_floss's exploration of differences, i.e., this book), but your year of high school Latin has been obscured by the fog of memory.
People You Can Impress: Roman emperors, lawyers, and grammar nerds.
The Quick Trick: E.g. means "for example"; i.e. means "that is." We at mental_floss remember this simply by employing Valley Girl speak. Where a fancypants Latinist would use e.g., a Valley Girl would use "like." And where the Latinist uses i.e., the Valley girl goes with "I mean." Like: "I love going out with Todd. He has, like, a really nice car. I mean, it cost a lot of money."
The Explanation: We will never understand why English abbreviations like BRB and LOL are derided as lazy, while Latin abbreviations are seen as the height of class. But now and again, it just sounds better to spice things up with a little dead language, and since Greek and Sanskrit both use unfamiliar alphabets, Latin's your best bet.
E.g. is short for exempli gratia, which literally means "by grace of example." I.e. is more straightforward: id est means "that is." The confusion stems from the fact that both abbreviations seek to clarify or focus a broad proposition, but e.g. is followed by a specific example, whereas i.e. is followed by a restatement.
Now that you know your i.e. from your e.g., we hereby provide a guide to other Latin abbreviations and phrases that some people use, even though the English language has already stolen all the Latin words it needs.
Other Helpful Latin Abbreviations:
C.f.: Often misused to mean "see, for instance," c.f. is actually short for confer. Confer is the imperative of conferre and means "compare" in Latin even though it means no such thing in English. Just remember c.f. should be used in English only to mean "compare with."
Etc.: Literally, "and the rest," etc. (the abbreviation of etcetera) indicates that the list it follows is a partial. For that reason, it's redundant, and therefore poor grammar, to say, "I love hair metal; e.g. Whitesnake, Poison, Damn Yankees, etc.," since the "for example" immediately makes it clear that the list is partial.
QED: An abbreviation for quod erat demonstradum that means "which was to be demonstrated." These days, QED generally means "Look, Mom, I proved it!" Mathematicians sometimes still end their proofs with "QED," and you sometimes hear lawyers say it, because laywers will say absolutely anything in Latin.
The article above was reprinted from the mental_floss book "What's the Difference?" with permission.
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