Dictionary.com
Thesaurus.com

keto

1 American  
[kee-toh] / ˈki toʊ /

adjective

Chemistry.
  1. of or derived from a ketone.


keto- 2 American  
  1. a combining form representing ketone in compound words.

    ketolysis.


keto- British  

combining form

  1. indicating that a chemical compound is a ketone or is derived from a ketone

    ketose

    ketoxime

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Usage

What does keto mean? Keto is short for ketogenic, referring to a diet that is low in carbohydrates but high in protein. While originating as a medical diet, it's popularly associated with weight loss.

Etymology

Origin of keto

First recorded in 1910–15; independent use of keto-

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

From low-carb ice cream and keto protein bars to "sugar-free" soda, erythritol has become a staple ingredient in many modern foods.

From Science Daily • Mar. 28, 2026

I had a keto diet for most of this tour, and I thought that when I got back to carbs, I’d be more in moderation with it.

From Los Angeles Times • Dec. 11, 2025

These people probably enjoy Ironman competitions, keto and intermittent fasting.

From The Wall Street Journal • Nov. 7, 2025

You have to do keto but also be vegan.

From Slate • Jan. 1, 2025

Here there was no doubt that the keto form, not the enol, was present.

From "Double Helix" by James D. Watson