At some point in your life, you’ve likely come across the abbreviations “i.e.” and “e.g.” It’s common to assume that they’re similar to “ex.,” often used as an abbreviation for “example.” But this isn’t quite correct, and misusing or misreading them can cause some confusion. So what’s the deal with “e.g.” and “i.e.” — and when, if ever, do we need to use them?
Trying to puzzle out what “e.g.” and “i.e.” stand for isn’t easy — at least in English. That’s because they’re derived from Latin phrases: Exempli gratia is Latin for “for example” or “for instance,” while id estis Latin for “that is to say” or “in other words.”
Both “e.g.” and “i.e” are still in widespread use today, but perhaps not surprisingly considering their Latin origins, they date back hundreds of years. There are examples of the phrase exempli gratia in writing from the late 16th century, and there is evidence that id est was used in Old English before 950 CE. The English usage of both abbreviations dates to the early 17th century.
Despite their shared Latin origins, “e.g.” and “i.e.” have distinct meanings and are not interchangeable. The former expands a statement by giving examples, while the latter restates or clarifies a statement with a more specific description.
It can be tricky to remember which one to use, but memory aids can help. Remind yourself that “e.g.” means “for example” by remembering “e” is for “example” or “examples: good.” To recall that “i.e.” means “in other words,” remember that “i” is for “in other words” or “in essence.”
The short answer? You probably don’t — at least not in casual emails, or even in most professional settings. However, these Latin abbreviations tend to appear in academic and legal documents, so it’s a good idea to know what they mean and how to use them.
When writing “e.g.” and “i.e.,” the abbreviations should be lowercase, unless used as the first word in a sentence, and each letter should be followed by a period. And while many style guides require that foreign-language words be italicized, such as exempli gratia and id est, there is no need to italicize “e.g.” and “i.e.” when they are in their abbreviated form. There’s also no need to add an additional period if either abbreviation comes at the end of a sentence. For example: “I couldn’t remember whether to use ‘e.g.’ or ‘i.e.'” However, if the abbreviation is in the middle of the sentence, a comma is always inserted after the abbreviation.
“Ex.” (with or without the period) is sometimes used as an abbreviation for “example” — perhaps if the writer couldn’t remember whether to use “e.g.” or “i.e.” or was concerned their audience wouldn’t know what “e.g.” meant. However, “ex.” can also be used as an abbreviation for other words — including “exchange,” “executive,” “exercise,” “express,” “extinct,” and “extra” — and “Ex.” (with a capital “E”) is the abbreviation for a book in the Bible, Exodus.
For the sake of clarity, consider spelling out “example,” or using “e.g.” instead.
