Q. Would you please explain when to use “e.g.” and when to use “i.e.?” Thank you.

A. Certainly. Both are abbreviations for Latin phrases: id est (“that is”) and exempli gratia (“for the sake of example”). So use “i.e.” when you want to rephrase something you’ve already said, and use “e.g.” when you want to offer an example. Put a comma before and after; avoid using both in the same sentence; and try not to use either in formal prose. And (a bonus tip) if you start a list with “e.g.,” there’s no need to put “etc.” at the end.

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The best ingredients for pizza are green—e.g., spinach, artichokes, and green peppers.

The best ingredients for pizza are green: spinach, olives, etc.