“Asymptomatic” vs. “Asymptotic” vs. “Asystematic”: Is There A Difference?

by John Kelly, Senior Research Editor at

Words that are hard to spell, sound alike, aren’t commonly used everyday, and have very technical meanings? They’re confusing!

And the trio asymptomatic, asymptotic, and asystematic? Well, they make for a perfect storm of confusion.

Let’s break down these words, all the way down to their nuts and bolts. Now, don’t be too daunted by all the etymology. We promise that knowing the deeper roots of these words will help you keep them apart—and build your vocabulary while doing it.

What does asymptomatic mean?

Asymptomatic means “showing no evidence of disease”—that is, not showing any symptoms. In medicine, a symptom is something that indicates a person has a disease. Fever, chills, cough, aches, and fatigue are all common symptoms of flus and other viral infections, for example.

Just because someone is asymptomatic doesn’t mean they aren’t infected with a disease. Let’s unpack that, just to be sure: You may not have symptoms of a disease (are asymptomatic), but you could still be infected by it.

An asymptomatic person may experience symptoms later, or they may never show them. During a disease outbreak, an asymptomatic carrier of disease can still spread the disease and not even realize it. (This is why it’s so important for people to practice social distancing and stay at home amid the coronavirus pandemic.)

When communicating important health and public safety information to the public, it can be effective to avoid a difficult, if useful, word like asymptomatic. Many people may not know what the word means or, just as understandably, confuse it with other words—like asymptotic or asystematic—a confusion that indeed surfaces in our search data! An alternative way to refer to someone who is asymptomatic is “showing no symptoms.”

Where does asymptomatic come from?

The word asymptomatic is first recorded in the 1930s. It is composed of the Greek-based prefix a-, meaning “not” or “without,” and symptomatic. Take note of this a-, as we are going to see again in our article.

Entering English in the late 1600s, symptomatic is an adjective form of symptom. Found even earlier around 1350–1400, the word symptom ultimately comes from the Greek word sýmptōma, meaning “occurrence.” Sýmptōma has a literal sense of “that which falls together with something.”

Care to dig even deeper? The Greek sýmptōma is made up of the combining form sym, a variant of syn meaning “together” or “with,” and a form of the verb píptein, meaning “to fall.” Take note of these roots, too; you will be fast friends with them by the end of this piece.

What does asymptotic mean?

For the word asymptotic, we need to move from health class to math class. Asymptotic is an adjective form of asymptote—which has nothing to do with medical symptoms.

An asymptote is “a straight line approached by a given curve as one of the variables in the equation of the curve approaches infinity.” In other words, the line and the curve get closer and closer and closer but, no matter how far out you follow them, they never meet. Yeah, we think an illustration is called for here:

So, if asymptomatic and asymptotic don’t overlap at all in their meanings, then why do they look so similar? Blame it on the ancient Greeks.

Asymptotic is recorded around 1665–75, and the noun asymptote slightly before it in 1650–60. Asymptote comes from the Greek asýmptōtos, composed of that same prefix a-, meaning “not” and “without,” and sýmptōtos, “falling together.” And this word sýmptōtos is made up of the same roots we encountered above in symptom.

Etymologically speaking, asymptomatic and asymptotic are almost one and the same … asymptotically close, you might say. But their senses went on to signify very different things.

The meaning of asystematic 

Compared to asymptomatic and asymptotic, asystematic is the rarest—although its opposite, systematic, is by far the most common. Like asymptomatic, however, asystematic can also be used in medicine.

Asystematic means “not systematic” in the sense of “not specific to a system or set of organs” in the body. It could be said that an asystematic disease, for example, is not confined to just one system, such as the respiratory or digestive systems.

Like asymptomatic and asymptotic, asystematic derives from Greek elements, including that same prefix a-, “not, without.” It’s rooted in the word system. Like asymptomatic and asymptotic, system features the combining form sym-, meaning “together, with.” System is ultimately from the Greek word sýstēma, “whole compounded of several parts,” and it has a literal sense of “standing together.”

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How to tell apart asymptomatic, asymptotic, and asystematic

If you come across or need to use one of these words and want to know which word is intended or called for, ask yourself:

  • Is the context concerning math? If yes, then asymptotic is probably meant.
  • Is the context concerning medical topics? If yes, then asymptomatic is probably meant. Asystematic is very rare, mostly found in older texts.

Another trick is to look or listen for key word elements:

  • asymptomatic: has two M’s; contains the word symptom, which you can hear pronounced in asymptomatic; is pronounced with a long A sound
  • asymptotic: cut off the -ic ending and you nearly have the noun asymptote; is pronounced with a short A sound
  • asystematic: contains the word system

What are some other words that share a root or element with asymptomatic?

We know the deep dives into the origins of these words was … a lot to process. But these roots appear in many other words in the English language. Knowing the roots of such words is useful, because you can use these roots to decode and make connections between other words.

Some common words that feature the prefix a- and its variant an-, meaning “not, without”:

Some common words that feature syn-/sym-, meaning “with, together”:

Can you think of more words? How can you use your knowledge of a- and syn- (and their variants) to break down the meaning of these words?

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