Common errors in the usage of abbreviations in scientific writing

Common errors in the usage of abbreviations in scientific writing

Abbreviations are shortened forms of words and phrases and are a common occurrence in research manuscripts as they can help make highly complex technical writing more concise and easier to read. However, they can also cause a lot of confusion, and make communication unclear if they are not used with caution. Consider these sentences:

One of the most important skills for proofreading a manuscript is ATD. Poor ATD can result in embarrassing factual errors like not defining abbreviations at first mention.

Confused what we are talking about? Don’t yet start looking up what ATD stands for. Here, we have used it to mean “attention to detail.” For all you knew, when you first read, it could have meant “advanced technology demonstration,” “achieving the dream,” or something else that does not quite make sense in the context of the sentence.

Here’s another example, this time, from the abstract of an actual manuscript:

We developed a program that included SST for students and CMT for teachers.

Either the abbreviations in this sentence are very common in the author’s specialized field or the author has coined them himself/herself. Because the author is so familiar with them, he/she may not have realized that the target readers, some of whom may not be from the same discipline, may not understand them. Ideally, the author should have written the sentence as follows:

We developed a program that included social skills training (SST) for students and classroom-management training (CMT) for teachers.

In this article, we will provide some tips on the use of abbreviations. Make sure you pay attention to these best practices when using abbreviations in your research writing.

1. Define abbreviations at first mention: Abbreviations should be defined at first mention in each of the following sections in your paper: title, abstract, text, each figure/table legend. Abbreviations work well when you want to reduce the number of words to use. But an abbreviation that is well known in one field may not be common in another.

Example: We analyzed the results of the computational fluid dynamics (CFD) simulations to determine fluid flow and to detect cavitation in centrifugal pumps.

In the above example, the term CFD is fairly common in mechanical/civil engineering fields, but might not be clear to an interdisciplinary audience. As a best practice, once you have finished writing the entire manuscript, use the “Find” or equivalent function of your word processor to locate abbreviations and check if they are defined.

2. Always consult the target journal’s guidelines on abbreviation usage:

  • Depending on their focus and target audience, many journals (either broad focus or narrow focus) provide a list of abbreviations that can be used without definition. For example, DNA and ANOVA are fairly common abbreviations that most journals will allow. However, while a mechanical engineering journal might allow the use of CFD without definition, it may not allow the use of FWHM (full-width-at-half-maximum).
  • Some journals ask that abbreviations be introduced only if the term is used 3 or more times in the text.
  • Some journals discourage the use of any abbreviations in the title and the abstract.
  • Terms like CFD are so common and unambiguous that they need not be defined.

3. Make sure you use abbreviations that are standard in your field: In the physical sciences, we often use shortened forms for elements (e.g., Si, Cu, C, O, N) and measurement units (e.g., s, h, min, m, kg, K, J). It should be noted that these shortened forms need not be explicitly defined upon first use, but should always be indicated using the standard format (spelling as well as capitalization).

4.  Preferred styles for using abbreviations:

  • When using abbreviations, it is useful to remember that just because an abbreviation is written in capitals does not mean that the capitalization must be retained when the abbreviation is set out in full. Capitalization is generally reserved only for given names or proper nouns.

Example: FFT is fast Fourier transform—“Fourier” is a given name of a person, so it is capitalized, but the other terms can be retained in lowercase lettering.

  • Some terms are usually indicated by uppercase as well as lowercase letters. Such terms are provided by most journals under an accepted list of terms that need not be defined. When a manuscript also contains other abbreviations that are defined with the same letters, the lowercase format is preferred for the well-known terms, as the competing terms are generally represented by uppercase letters.

Examples: Alternating current (AC/ac), direct current (DC/dc), root mean square (RMS/rms), rotations/revolutions per minute (RPM/rpm).

These terms are acceptable in both uppercase as well as lowercase lettering. However, when there are other competing terms in the same manuscript, the priority of using uppercase lettering goes to the less common term [digital communication (DC) uses uppercase lettering and direct current (dc) uses lowercase letters].

  • As a matter of style, most journals advise authors not to start a sentence with an abbreviation. In such cases, the term is spelled out or the sentence is rephrased.

Examples:  Figure (Fig.), Reference (Ref.), Equation (Eq.), Section (Sect.), Chapter (Ch.)

However, acronyms are generally acceptable at the beginning of a sentence, either because they are words in their own right (such as laser and radar) or represent names of organizations (such as NASA and CERN). Further, if journal formatting specifically requires the use of a particular abbreviated form, then these are allowed at the beginning of a sentence (e.g., IEEE journals generally require that “Figure” always be abbreviated, even at the beginning of a sentence).

5. Be careful when using alphanumeric abbreviations: Many shortened forms are alphanumeric, and generally, there is a rationale behind these combinations. The numerals before/after the letters simply indicate a detail associated with a parameter. For example, a system may have different degrees of freedom depending on the number of independent variables (2-DoF, 6-DoF, n-DoF). Over time, the numerals become part of the names (2D, 3D). Appropriate combinations of letters and numerals are therefore chosen depending on the meanings that need to be conveyed.

Example 1: n-DoF (n degrees of freedom)

Here, “n” represents the number of independent parameters of the system.

Example 2: PCA1/PCA2

This is a brief way of representing the principal scores of an analysis. The numbers indicate the order or priority of the set of correlations between components and variables.

Always confirm if the designations you are using convey your meaning accurately. In the above examples, the positions of the letters and numerals cannot be interchanged, as this would make the notation non-standard.

6. Use of Latin abbreviations: Scientific writing often uses a few Latin abbreviations, such as “e.g.”, “i.e.”, and “et al.”  All of these are used in lowercase and the usage of period should be as per convention. Missing or misplacing a period is akin to misspelling for these abbreviations. Now let’s take a deeper look at these:

  • The abbreviation “e.g.” stands for exempli gratia, which means “for example” and “i.e.” stands for id est, meaning “that is.” These two abbreviations are always followed by a comma in American English (no comma is required in British English). When used inline, they are either spelled out or offset by commas. However, it is always appropriate to avoid mixing styles. In the examples below, both inline and parenthesized versions are presented in American English convention.


1. Some studies (e.g., Jenkins & Morgan, 2010) have supported this conclusion. Others—for example, Chang (2004)—disagreed.

2. Some studies, e.g., Jenkins & Morgan (2010), have supported this conclusion. Others, e.g., Chang (2004), disagreed.

3. Two types of defects (i.e., cracks and bends) were investigated for each alloy.

4. Two types of defects, i.e., cracks and bends, were investigated for each alloy.

  • One of the trickiest abbreviations used in scientific writing is “et al.” as it is often misspelled or used incorrectly. This term stands for et alii, meaning “and others”. This abbreviation is used only to shorten lists of names, such as those in in-text citations or references, and can be used anywhere in the text so long as it is preceded by a name. Any punctuation before or after this term is determined by the formatting style alone. In the examples below, a name precedes the term and additional punctuation depends on formatting style (APA is used here).


1. Bjeg et al. (2016) show that the aspect ratio of the room determines whether the airflow is two- or three-dimensional.

2. Previous reports (Bjeg et al., 2016) indicate that the aspect ratio of a room determines whether the airflow is two- or three-dimensional.


We have looked at some general styles and conventions for using abbreviations. When using abbreviations or acronyms, it is always advisable to verify the term as well as its usage, particularly with respect to capitalization, standardized convention, spelling, and use of period(s). In addition to these, individual journals may have special instructions regarding approved terms and styles. These requirements should be specifically noted and followed to achieve a concise, technically correct, and well-written manuscript.

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