Laser vs. Lazer: Which One Is Right?

laser pointer

Laser vs. Lazer: Which One Is Right?

Certain words — no matter how good a speller you are — are just plain elusive. It doesn’t help that countless words in the dictionary have multiple acceptable spellings. “Acknowledgment” and “acknowledgement.” “Doughnut” and “donut.” “Caliber” and “calibre.” “Enclose” and “inclose.” In these cases, both spellings are considered acceptable. But what about those instances where two spellings are circulated, but only one is correct? Take laser vs lazer. Which spelling is the right spelling? Let’s set the record straight, once and for all.

Laser vs. Lazer: Side by Side Comparison

What Is a Laser?What is a Lazer?
A super narrow, single-colored beam of light.Common misspelling of “laser.”
Used in surgery, engravings, and productions.Not a real word in the scientific community.
Acronym for “Light Amplification by Stimulated Emission of Radiation.”Brand name for various radio stations, cars, and so on.

Laser vs. Lazer: Differences Explained

Experiment with lasers in the laboratory of Photonics
Is there a difference between the spelling of laser vs. lazer?


The “laser” vs. “lazer” debate rests on the shoulders of one single letter. Before we even touch on the difference in definitions, this difference in spellings is the most glaringly obvious. So… which is it? Laser with an S or lazer with a Z?

Unless we’re talking about a product or service intentionally misspelling the word, the correct way to spell it is the former over the latter every single time. Laser, or “Light Amplification by Stimulated Emission of Radiation,” will always be spelled with an S because it’s an acronym.

In the word “laser,” the letter S stands for “Stimulated.” While it might sound obvious, there’s no room for a Z here because “Stimulated” is not spelled with a Z. The only time you’ll see the word “lazer” over “laser” is when a brand name purposely misspells the word for marketing purposes.

This leads us to the other key difference: the contrasting definitions of laser vs. lazer. A laser is a highly concentrated monochromatic light beam that can drill, cut, or slice through matter through the magic of stimulated photons. A lazer, by comparison, has no definition. It’s not a real word.

5 Must-Know Facts About Laser vs. Lazer

  • Lasers produce beams of concentrated light through the stimulation of atoms. These atoms then release powerful photons focused in a tight line that can span long distances with ease.
  • Lasers are used everywhere from eye surgeries to jewelry engraving to fiber optic cables to concert light shows and beyond.
  • There are many different types of lasers. These variants include solid-state, gas, and semiconductor lasers. Each variant generates light using a different method of stimulation.
  • Lasers emit light that’s coherent. In other words, the light from each proton will always interfere with the light from the other protons. This creates precise, monochromatic beams of energy.
  • Lasers are nothing like flashlights. Direct exposure to laser beams can seriously harm your eyes, skin, and other sensitive things like camera lenses and televisions.

The History of Lasers

Direct Laser Sintering 3D printing
The science behind laser technology dates back over a century.


Long before lasers were ever brought to life, they only existed as a theory. This theoretical foundation dates back to none other than Albert Einstein himself. Back in 1917, Albert Einstein penned “On the Quantum Theory of Radiation.” Einstein based his laser concept on a rederivation of an existing law of radiation.

His concept toyed with the idea of absorption and emission of electromagnetic radiation. It would take decades of continued research and mathematics for his concepts to become reality. In 1951, scientists Joseph Weber, Charles H. Townes, James P. Gordon, and Herbert J. Zeiger produced the world’s first working microwave amplifier.

This later became known as a “maser,” just one letter (and a handful of scientific steps) shy of “laser.” The concept was more or less the same but with microwave radiation rather than electromagnetic radiation. It would take some another several years of research and development for the maser to become a laser.

Between 1957 and 1958, Townes and Arthur Leonard Schawlow, graduate student Gordon Gould, and engineer Jun-ichi Nishizawa all developed their own separate takes on “optical masers.” We now know these under a different name: laser. Gould made it official with the first use of the “LASER” acronym in 1959.

What Does Lazer Mean?

Comparing “laser” vs. “lazer,” the latter doesn’t have an exact meaning. At least, not in the same sense that “laser” does. From the electronic music group Major Lazer to radio stations colloquially dubbed “The Lazer,” the spelling swaps the “S” with a “Z” for a phonetic spelling that looks edgier, cooler, or more abstract than the traditional spelling of the acronym.

“Lazer” is also commonly used to refer to the game of laser tag. There’s even a series of films that utilize this spelling: Lazer Team (2015) and Lazer Team 2 (2017). These two productions hail from the team behind the YouTube channel Rooster Teeth. In this light, it seems misspelling laser with a Z can add a touch of lighthearted youthfulness to a brand.

No matter which way you cut it — no laser pun intended — “lazer” is not a real word. There’s no scientific scenario where this word would be accepted. The academic community is so strict about this spelling because of what we’ve said: It’s an acronym. It wouldn’t be acceptable to misspell other acronyms like radar or sonar, and the same goes for laser.

Laser vs. Lazer: Which Spelling Should You Use?

Between “laser” vs. “lazer,” you should use the first spelling every time. The “lazer” misspelling is usually only seen in brand names and other titles. It’s nothing more than a way to grab the consumer’s attention. “Laser” is the one and only way to spell it accurately. From gas lasers to fiber lasers, solid-state lasers to semiconductor lasers, it’s “S” over “Z” every single time. Alas, the two will surely continue to be mixed up and used interchangeably. Nevertheless, the fact remains: It’s “laser,” not “lazer.”

Frequently Asked Questions

What is a laser?

A laser is a device that channels a focused, coherent beam of monochromatic light. It’s an acronym short for “Light Amplification by Stimulated Emission of Radiation.” It works through the science of photons emitted from stimulated atoms. It’s not to be confused with “lazer,” which is a popular misspelling of the word.

What does "laser" stand for?

The acronym “laser” stands for “Light Amplification by Stimulated Emission of Radiation.” It describes the scientific process and technology used to create a concentrated beam of light. It is not to be confused with a “maser,” which uses microwave technology instead of electromagnetic technology.

Is "lazer" an acceptable alternative spelling of “laser”?

“Lazer” is often confused for “laser,” but the truth is that this informal variant is not a correct spelling for the word. There’s no wiggle room here because “laser” is an acronym first and foremost. The “S” stands for “Stimulated,” which is not spelled with a Z. It’s nevertheless used quite frequently, but it’s not a standard or formally accepted spelling.

Why do people use "lazer" instead of "laser"?

The use of “lazer” instead of “laser” can be credited to everything from typographical error to informal slang to stylistic preference. It’s possible someone could simply misspell the word through improper phonetics, but it’s more likely to see “lazer” used as a branding tool to look youthful or cool.

Are "laser" and "lazer" interchangeable?

Both terms are often used interchangeably, both in everyday language and casual conversation, but “laser” is the only true way to spell the word. Over time, both spellings have been established and universally recognized — however, “laser” is the only accepted and standard spelling in scientific, academic, and formal contexts.

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