I often see mistakes with “i.e.” and “e.g.” when writers are trying to give examples or trying to elaborate.

The term “i.e.” is an abbreviation for the Latin phrase “id est” and means “that is” in English.

The term “e.g.” is an abbreviation for the Latin phrase “exempli gratia” and means “for the sake of example” (more simply, “for example”) in English.

One should follow either abbreviation immediately by a comma and a space before one gives the elaboration (in the case of “i.e.”) or the example (in the case of “e.g.”).

Examples:

“The mountain summit (i.e., the peak of the mountain) ….”

“Felines (e.g., lions, tigers, and cats) ….”