Today, we’re going to talk about what symbols, abbreviations, etc., to use when, i.e., you want to give a list of things, happenings, people, et al., and want to leave some out, e.g., the things, or include them all.
All of those expressions above—“i.e.,” “e.g.,” “et al.,” and “etc.”— are signals that you either are about to elaborate on something or expect the readers to understand that you are not being comprehensive. Each has a specific use, though people sometimes mix them up.
Unfortunately, this will involve a little Latin, and there’s some poetic justice that abbreviations are used to indicate abbreviated information, but never mind that.
Let’s get rid of the easy one first: “etc.” Of course, “etc.” is short for “etcetera” (sometimes spelled “et cetera), Latin for “and other such things.” It’s handy when you’re writing about, say, dog breeds, and you want to list only a few. The implication is that the list is too long to mention, so don’t use “etc.” if you are listing three of five things. And don’t do as the King of Siam did and use “et cetera, et cetera, et cetera” when you can’t think of what else to say.
“Et al.” is an abbreviation of “et alii,” or “and others.” Note that there is no period after “et,” since it is not an abbreviation. Because it’s not “and other things,” that’s a good clue about when to use it: with people. If you are listing prominent Republicans, you can say “Mitt Romney, Ronald Reagan, Barry Goldwater et al.” (The Associated Press Stylebook, which wants a comma before “etc.,” is not in favor of a comma before “et al.” when used in a list; The Chicago Manual of Style wants a comma before both.) Garner’s Modern American Usage says that the “misuse” of “etc.” instead of “et al.” when people are involved is at Stage 3 of the five-stage Language-Change Index, meaning you’d get probation instead of jail for using it.
Now, on to “i.e.” It stands for “id est,” or “that is.” Grammatically speaking, you shouldn’t use “i.e.” unless you are listing everything in a set; if you want to leave things out, you want “e.g.” (“example gratia,” or “for example”). Mignon Fogarty, “Grammar Girl,” talks about this more in her “Quick and Dirty Tips for Better Writing.” Generally, if you like only two colors, you should say “I like two colors, i.e., blue and red.” If you like more, you should say, “I like some colors, e.g., blue and red. (Most usage guides want commas before both and after those expressions.)
But these get mixed up, too: Garner’s lists “e.g.” misused for “i.e.” at Stage 2, meaning you might spend a year behind bars if bad grammar were really a crime.
Of course, you can write ad usum* and skip the Latin completely. Nothing wrong with saying, “and others,” “for example,” “such as,” or “including.” They’ll still understand.
*“to usage,” or “for the use of,” in this case, for the use of your readers.