What Is Tautology?

Tautology is the needless repetition of a single concept. For example:
  • He left at 3 am in the morning. wrong cross
  • (As "am" means "in the morning," the phrase "3 am in the morning" is a tautology. It expresses a single concept twice.)
This tautology can be corrected by removing one of the repeats.
  • He left at 3 am in the morning. correct tick
  • He left at 3 am in the morning. correct tick

Table of Contents

  • Easy Examples of Tautology
  • Some Harder Examples of Tautology
  • Real-Life Examples of Tautology
  • Video Lesson
  • Why Tautology Is Important
  • Test Time!
tautology examples
In most tautologies, the concept is repeated because a word is inherent in another. For example:
  • Unmarried bachelors tend to buy fancy cars. wrong cross
  • (In this example, the word "unmarried" is inherent in the word "bachelor," which means an unmarried man.)
This tautology can only be corrected by removing the word "unmarried."
  • Unmarried Bachelors tend to buy fancy cars. correct tick
  • Unmarried bachelors tend to buy fancy cars. wrong cross
The adjective from tautology is "tautological." As tautological expressions include redundant words, they are usually considered writing errors.

Formal Definition

Tautology: the use of two words or phrases that express the same meaning, in a way that is unnecessary and usually unintentional.
Cambridge Dictionary

Easy Examples of Tautology

Here are some examples of tautology. In each example, the tautological expression is shaded.
  • At that moment in time, the stars dimmed. wrong cross
  • (It is always a moment in time. The concept of time is inherent in the word "moment.")
  • This is a new innovation. wrong cross
  • (Innovations are always new. The concept of new is inherent in "innovation.")
  • The vote was totally unanimous. wrong cross
  • (The word "totally" doesn't add anything. "Totally" is inherent in "unanimous.")
  • He was in a three-way love triangle. wrong cross
  • (The word "three-way" doesn't add anything. It is inherent in "triangle.")

Some Harder Examples of Tautology

Sometimes, tautologies are harder to spot.
  • The reason is because he left during the dinner. wrong cross
  • (The word "because" doesn't add anything. It means "for the reason that.")
  • He was the reason why I left the job.wrong cross
  • (This example can be corrected by removing "the reason" or "why." They do the same job. "Why" means "for what reason." )
  • In our assessment, we think he is alive. wrong cross
  • ("In our assessment" and "we think" do the same job.)
Let's get technical for a second. In the examples below, quotation marks are used to denote "so-called"; therefore, the use of the word "so-called" is needless repetition.
  • He placed the chicken on the so-called "clean" surface. wrong cross
  • His so-called "mates" left him in the tree. wrong cross
Technically, there is no need for the word "so-called" in these two examples because that's what the quotation marks mean.

Real-Life Examples of Tautology

  • Many people's commute back and forth to work requires them to spend hours behind the wheel each day. wrong cross
  • (The words "back and forth" don't add anything.)
  • That's one of the great advantages of age...you can throw temper tantrums, and nobody minds. (Author James Lee Burke) wrong cross
  • (The word "temper" doesn't add anything.)
On occasion though, a tautological phrase reads better than the non-tautological version or gives the emphasis sought by the author.
  • I asked the question, "Will I ever perform again?" (Musician Brian Harvey)
  • (The words "the question" could be removed, but the result would be less empathic.)
  • Everyone is the sum total of past experiences. A character doesn't just spring to life at age thirty. (Writer Kelley Armstrong)
  • (The words "total" and "past" could be removed, but "sum total" and "past experiences" are set terms.)
  • Of course, everybody's thinking evolves over time. (Ethiopian politician Meles Zenawi)
  • (The words "over time" could be removed, but the emphasis on time would be lost.)

Video Lesson

Here is a video summarizing this lesson on tautology. video lesson

Are you a visual learner? Do you prefer video to text? Here is a list of all our grammar videos.

Why Tautology Is Important

Spotting tautology is useful for eliminating redundant words, which will not only reduce your word count but also portray you as a clear thinker. Here are some tautological terms that could be shortened safely (i.e., with no loss of meaning):
  • Armed gunman
  • Attach together
  • Depreciate in value
  • Warn in advance
Be careful though. Sometimes, a tautological term work will work better for you than the non-tautological version.
  • I need to ask the question.
  • We evolve over time.
Sometimes, you have to think whether something really is a tautology.

Example 1:

  • She died of a fatal dose of heroin.
Argument For: You don't need the word "fatal."
Argument Against: She might have died from a non-fatal dose, i.e., one that wouldn't kill most people.

Example 2:

  • Present a short summary.
Argument For: Summaries are always short.
Argument Against: Er, no they're not.

Example 3:

  • Enter your PIN number in the ATM machine.
Argument For: The N in PIN stands for Number, and the M in ATM stands for Machine.
Argument Against: Yeah, okay. But, PIN and ATM have become standalone terms these days. It's helpful to put the words "number" and "machine" to ensure everyone understands.

Key Point

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This page was written by Craig Shrives.