Two famous, latin abbreviations that so many people seem to get wrong.
i.e. is short for “id est” and should be used for “that is.”
- I strongly recommend the driver of the automobile cease their forward movement at this time, i.e, STOP!
- This weekend, I played with my kids, ran errands, baked bread, cleaned the house, washed the dog, updated my blog, balanced my checkbook, and painted the garage; i.e., I’m tired.
- My child is a natural at sports (i.e., baseball, football, and tennis).
- When the little hand and the big hand are both pointing to 12 (i.e., straight up), it will be noon.
e.g. is short for “exempli gratia” and should be used for “for example.”
- I carry a lot of things in my purse, e.g., my cell phone, wallet, MP3 player, and my glasses.
- A prime number is one that can only be evenly divided by itself and the number one, e.g., one, two, three, five, seven…
The trick is that they often seem interchangeable, as in the following sentences.
- I love vegetables, i.e., things like carrots and celery.
- I love vegetables, e.g., carrots, celery, corn, and so on.
The difference is that the first one (with the “i.e.”) is clarifying exactly what is meant by “vegetables,” whereas the second one is giving actual examples of the loved vegetables.
Still having trouble remembering? Here’s a handy mnemonic device I saw over at Grammar Girl‘s:
A few listeners have also written in to say that they remember the difference between i.e. and e.g. by imagining that i.e. means “in essence,” and e.g. sounds like “egg sample,” and those are good memory tricks too.
As to punctuation, the correct way to write these is with a period after both letters (“i.e.” and “e.g.”), followed by a comma.