The word is spelled C-A-L-O-R-I-E-S. The singular form is “calorie,” and the plural is “calories.” An older, less common variant spelling is “calory,” but this form has largely fallen out of use in modern English.
How to Break It Down
The word has three syllables: cal-o-rie. Merriam-Webster gives two accepted pronunciations: “KAL-uh-ree” and “KAL-ree,” where the middle syllable is either lightly voiced or dropped entirely. Both are standard.
The most common misspellings include “caloreys,” “caleries,” and “calorys.” The ending follows the same pattern as words like “cookie” or “brownie,” where the singular ends in “-ie” and the plural simply adds an “-s.”
Where the Word Comes From
Calorie comes from the Latin word “calor,” meaning heat. A French scientist named Nicholas Clément first used the term in lectures on heat engines in Paris between 1819 and 1824. The word entered English in 1863 through a translation of a popular French physics textbook, which defined a Calorie as the heat needed to raise the temperature of 1 kilogram of water by 1 degree Celsius.
Why You Sometimes See a Capital “C”
In science, there are actually two versions of the calorie. A lowercase “calorie” (cal) is the energy needed to heat 1 gram of water by 1 degree Celsius. An uppercase “Calorie” (Cal) equals 1,000 of those small calories, which is why it’s also called a kilocalorie (kcal). The calories listed on food labels are always the big-C Calories, meaning kilocalories, even though the packaging typically uses a lowercase “c.”
One food calorie equals about 4.184 joules, the standard energy unit used in physics. Some countries, particularly Australia and New Zealand, label food energy in kilojoules rather than calories. A snack labeled 100 calories in the U.S. would appear as roughly 418 kilojoules on an Australian label.
How It Appears on Food Labels
U.S. food labels regulated by the FDA use the word “Calories” with a capital C. The FDA permits three label formats: “Calories, total,” “Total calories,” or simply “Calories.” Manufacturers can also add the word “Energy” in parentheses as a synonym. Calorie counts on labels are rounded to the nearest 5-calorie increment for foods with 50 calories or fewer per serving, and to the nearest 10 calories above that. Anything under 5 calories per serving can legally be listed as zero.