Sorting Out “i.e.,” “e.g.,” and “etc.”

The abbreviations “i.e.,” “e.g.,” and “etc.” are all shortened forms of Latin phrases that function as links to connect additional information to a sentence. While use of “i.e.” and “e.g.” will help to clarify a thought, use of “etc.” will muddle it. The explanations and examples below will help you use these abbreviations appropriately in your research papers.

What is the difference between “i.e.” and “e.g.?”

The abbreviation “i.e.” is the shortened form of the Latin expression id est, which translates to “in other words” or “that is.” Use “i.e.” when you want to clarify what you previously said in your statement. For example, you could write, “The therapy needed to be administered for a long time, i.e., 7–8 months.” Often “i.e.” is preferred only when the phrase is enclosed in parentheses; otherwise, the full term is written: “The therapy needed to be administered for a long time (i.e., 7–8 months)” or “The therapy needed to be administered for a long time, that is, 7–8 months.”

The abbreviation “e.g.” is the shortened form of the Latin expression exempli gratia, which means “for example.” This phrase comes in handy when you want to provide an example to illustrate a point. Let’s look at “e.g.” used in a sentence: “We collected leaves from various types of trees, e.g., maple, birch, oak, and ash.” Here, you are providing a list of some of the types of trees from which the leaves were obtained. As with “i.e.,” “e.g.” is often used only in a phrase enclosed in parentheses: “We collected leaves from various types of trees (e.g., maple, birch, oak, and ash)” or “We collected leaves from various types of trees, for example, maple, birch, oak, and ash.”

A good way to be sure you are using the two abbreviations correctly is to remove “i.e.” or “e.g.” and substitute “in other words” or “for example,” respectively. If the sentence is still true and makes sense, then you know you have used the correct phrase. In addition, you can simply remember that as “e.g.” starts with an “e,” it means you are about to provide an example, which also begins with an “e.”

A few rules apply to both “i.e.” and “e.g.”:


What does “etc.” mean and why should it be used with caution or avoided?

The abbreviation “etc.” is the shortened form of the Latin phrase et cetera, which means “and other similar things” or “and the rest.” When you add “etc.” to the end of a list of items, you are indicating that the list is not complete. However, authors of scientific papers should be as specific as possible when presenting information. When a list is followed by “etc.,” you are leaving it to the reader to speculate what the unidentified items are. For example, if you write, “The questionnaire includes age, gender, etc.,” the readers are left wondering what other characteristics are included. It is better to simply list all of the items: The questionnaire includes five demographic characteristics, namely, age, gender, education level, residence, and monthly income.”

Of course, sometimes it is not practical to include a full list. In these cases, instead of using “etc.,” you can use “such as,” “including,” or “for example,” as in, “Gold nanoparticles have various biomedical applications, including use in drug delivery, cancer treatment, and biomedical imaging.” There is no need to tack on “etc.” to the end of this list because “including” already lets the reader know that you are not providing a complete list.

In sum, it is always best to use exact language in scientific manuscripts so that readers are not left confused or misinformed.