Corn syrup is a food syrup that is made from the starch of corn (called maize in some countries) and contains varying amounts of maltose and higher oligosaccharides, depending on the grade. Corn syrup, also known as glucose syrup to confectioners, is used in foods to soften texture, add volume, prevent crystallization of sugar, and enhance flavor. Corn syrup is distinct from high-fructose corn syrup (HFCS), which is manufactured from corn syrup by converting a large proportion of its glucose into fructose using the enzyme D-xylose isomerase, thus producing a sweeter compound due to higher levels of fructose.
The more general term glucose syrup is often used synonymously with corn syrup since glucose syrup in the United States is most commonly made from corn starch. Technically, glucose syrup is any liquid starch hydrolysate of mono-, di-, and higher-saccharides and can be made from any source of starch; wheat, tapioca, and potatoes are the most common other sources.