My friend Antonio recently asked me about i.e. and e.g. These Latin abbreviations, which are pretty popular in English, get confused quite a bit. It's easy to see why.
Even people who use the abbreviations aren't likely to know what they stand for. They're just letters, not closely associated with English words. So unlike FBI and CIA, whose spelled-out versions are well known, i.e. and e.g. are more likely to get mixed up.
That's part of the reason I've never felt comfortable writing about the topic here. But that's not the main reason. A far more powerful deterrent has been my fear that if I wrote about i.e. and e.g. I'd have to start a sentence with one of these terms.
Ever seen either of these at the head of a sentence? I hadn't. As a result, when I embark on a sentence like, "E.g. means such and such," that capital letter E looks funny to me — so funny that my confidence in writing about the subject is undermined.
Reference books don't specifically address capitalization matters like these. If you want to know whether an abbreviation that normally starts with a lowercase letter should be capitalized at the beginning of a sentence, good luck finding a definitive answer. There's just no source out there that's both authoritative enough to give meaningful answers and specific enough to address this question.
But when Antonio asked, I knew I needed to get over this little insecurity (or at least write around it with lots of careful arrangement of my sentences).
Funny what a little research can do. In the first reference book I opened to learn about these two abbreviations, Merriam Webster's Dictionary of English Usage, my eye went straight to this line: "E.g. introduces one or more examples that illustrate something stated directly or shortly before it."
True, I didn't have a resource to tell me straight out how to capitalize e.g. at the head of a sentence. But I had the next best thing: an example. So if you want to do as Merriam's does (which I do), just capitalize the first letter of either of these abbreviations if it happens to appear at the start of your sentence.
Now here's how to keep them straight.
E.g. is short for the Latin term "exempli gratia." It means "for example." A handy mnemonic device writes itself: E.g. starts with E and so does "example." And here's an example of how to use it: "Borrow only from reputable lenders (e.g. banks and credit unions)."
As in this example, e.g., and i.e., too, often appear in parentheses. But you can skip the parentheses by just putting a comma before either of these terms: "Borrow only from reputable lenders, e.g. banks and credit unions."
I.e. is short for the Latin term "id est," which means "that is." Merriam adds this clarification: "I.e., like 'that is,' typically introduces a rewording or a clarification of a statement that has just been made or of a word that has just been used."
Here's an example from a 1984 Houston Post article: "It is money that wasn't absorbed by government, i.e. the administration tax cuts, that is spurring current growth."
Yes, there's some gray area between these terms. They overlap a bit. But the easiest way to keep e.g. and i.e. straight is simply to remember that e.g. introduces an example while i.e. means "that is."