What does carb mean?
A carb, short for carbohydrate, is one of the three main macronutrients the body uses for energy, alongside protein and fat. Chemically, carbohydrates are compounds of carbon, hydrogen, and oxygen that range from simple sugars like glucose to complex starches and fibres. In everyday use, however, people rarely mean the chemistry: "carb" has become the standard informal term for the foods that supply these nutrients — bread, rice, pasta, potatoes, and cereals. It is overwhelmingly a word of kitchens, gyms, and diet conversations rather than laboratories, appearing most often in the plural ("cutting carbs", "loading up on carbs"). Its connotations are mixed: athletes deliberately consume extra carbs to fuel performance through a practice known as carb loading, while popular weight-loss diets treat them as something to limit. The clipped form reflects modern English's fondness for abbreviating long technical words once they enter daily speech.
nounAn informal shortening of "carbohydrate": any of a class of organic compounds that supply energy to the body, or a food rich in them such as bread, rice, or pasta.
- A carbohydrate: an energy-supplying compound found in foods like bread, rice, potatoes, and pasta.
- A food that is rich in carbohydrates (informal, often plural): "I'm cutting out carbs this month."
"She cut back on carbs before the marathon to train her body to burn fat."
"Athletes often eat extra carbs in the days before a long race."
"This bread has fewer carbs than most."
The plural is by far the most common form in everyday speech, especially when discussing diets or meals.
"He's avoiding carbs after six o'clock."
The word "carbohydrate" was coined in the 19th century from carbon plus hydrate — chemists literally saw sugars as "watered carbon," and "carb" is its gym-bag nickname.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of carb
"Carb" is a late-20th-century clipping of "carbohydrate," itself a 19th-century coinage combining "carbo-" (from Latin carbo, meaning coal or charcoal) with "hydrate," reflecting early chemists' observation that these compounds contain hydrogen and oxygen in the proportions of water. The Latin root carbo also gives English "carbon" and "carbonate." The shortened form spread through American fitness and dieting culture before becoming common throughout the English-speaking world.
Related word forms
How carb is actually used
Informal register; almost always used in the plural when referring to foods. Ubiquitous in fitness, dieting, and sports-nutrition contexts.
Easily confused with carb
"Crab" is a crustacean or a verb meaning to complain, while "carb" refers to carbohydrates — they differ only slightly in spelling and rhyme closely in some accents.