Grammar Rules for ‘i.e.’ vs. ‘e.g.’: When to Use ‘i.e.’ and ‘e.g’

“I.e.” is an abbreviation of the Latin phrase “id est,” which translates to “that is.” The phrase “id est” is typically used in more formal writing. Still, in modern colloquial English, it translates to “in other words” or “in essence.” When “i.e.” appears in the middle of a sentence—often after a comma, within a parenthetical, or enclosed in em dashes—it introduces an elaboration on an aforementioned topic or idea.

You can use “i.e.” within a sentence to further a concept or to clarify an idea, using it as a substitute for “in other words.” Consider these three examples:

1. 1. “As a theatergoer, I enjoy realism—i.e., less stylized plays whose settings, characters, and plotlines mimic ones seen in everyday life.” In this example, you can replace i.e. with “in essence.”
2. 2. “Managers will receive a staff discount, i.e., 50 percent.” Here, you can easily replace the i.e. with “that is.” The i.e. defines what the staff discount is.
3. 3. “The restaurant is past capacity (i.e., there are over 100 people indoors).” Here, i.e. qualifies what counts as overcapacity for the restaurant.

“E.g.” is an abbreviation for the Latin phrase “exempli gratia,” meaning “for the sake of example.” Put more simply, “e.g.” can stand for “for example.” You can use “e.g.” to illustrate examples within a sentence.

You can employ ‘e.g.’ after a comma or an em dash, or between parentheses in a sentence to illustrate examples. Consider the following examples:

1. 1. “I love stone fruits, e.g., peaches, plums, and cherries.” This use of “e.g.” stands in for the phrase “for the sake of example.”
2. 2. “Some of my favorite movies are horror films (e.g., Midsommar, Us, A Quiet Place).” In this example, “e.g.” appears within parentheses, introducing examples of horror movies the speaker likes.
3. 3. “She’s traveled to many South American countries—e.g., Peru, Venezuela, Chile, and Brazil.” Here, “e.g.” highlights a partial list of countries the subject in the sentence has visited.

“I.e.” and “e.g.” may seem like synonyms, but uses for these Latin abbreviations differ. Use a mnemonic device to help you remember whether to use “i.e.” or “e.g.”: The first letter of “e.g.” can stand for “example,” and “i.e.” can stand for “in essence.” The use of “i.e.” restates a previous idea in a different (and often more colloquial) way. “E.g.” offers specifics that exemplify the stated concept. For both “e.g.” and “i.e.”, many style guides dictate lowercasing the letters and placing a period after each. Additionally, you do not have to write “i.e.” and “e.g.” in italics.

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