What is the difference between sweetcorn and corn?

Corn is just regular corn and sweet corn is corn you brush with honey.

Sweet corn is what we eat in either the can or frozen or fresh off the cob.

Regular corn is what is used to make bio fuels and also for use as a cattle feed.

sweet corn is soft and more sugar, and is meant for humans.

field corn is tougher, less sweet, and the plants are more productive per acre.

Corn is endangered due to cloning, and also heavily GMO for roundup usage.

The variety of corn we enjoy eating is called sweet corn, which does not grow nearly as tall as field corn (another identifiable difference). Sweet corn has a higher sugar content than cow corn, and is picked while immature, before the sugar has a chance to turn into starch. 

I believe a higher sugar content.

Sweet corn is grown for people corn like canned corn or corn on the cob .  The other corn, grain corn, is for animal feed, fuel alcohol, and I think sweetener .

Sweet corn is a vegetable. It can be abbreviated to simply corn sometimes. 

Corn is considered a grain like wheat. It is for example used in the food industry in to make corn masa for the tortilla chips (Doritos etc). 

Sweetcorn is edible for humans. Other corn is only good for making ethanol, tortillas, high fructose corn syrup, and animal feed. 

What Americans call "corn" Brits call "sweetcorn" because in the UK "corn" refers to any grain, but especially to wheat.