Corn on the cob is a culinary term for a cooked ear of sweet corn (maize) eaten directly off the cob. The ear is picked while the endosperm is in the "milk stage" so that the kernels are still tender. Ears of corn are steamed, boiled, or grilled usually without their green husks, or roasted with them. The husk leaves are removed before serving.
Cooked corn on the cob with serving sticks
Preparing roasted corn on the cob in Loikaw (Myanmar).
Brazilian corn on the cob at Barra da Tijuca, Rio de Janeiro
Cooking corn on the cob by boiling
Sweet corn, also called sweetcorn, sugar corn and pole corn, is a variety of corn grown for human consumption with a high sugar content. Sweet corn is the result of a naturally occurring recessive mutation in the genes which control conversion of sugar to starch inside the endosperm of the corn kernel. Sweet corn is picked when still immature and prepared and eaten as a vegetable, rather than field corn, which is harvested when the kernels are dry and mature. Since the process of maturation involves converting sugar to starch, sweet corn stores poorly and must be eaten fresh, canned, or frozen, before the kernels become tough and starchy.
Husked sweet corn
Loose kernels of sweet corn
Young sweet corn
The same rows of corn 41 days later at maturity