In German it is 'Mais'... and 'Korn' means any kind of grain.
English is weird sometimes.
Yes there are different varieties and the one you think of is sweet corn.
Sweet corn has a certain mutation, which makes it sugary and juicy.
98% of maize is not the sweet, juicy kind; There are varieties for grinding into corn flour, for animal feed and some are best just for bio-fuel.
I will be growing Golden Bantam sweet corn, which is by far the most popular sweet variety.
Just by looking at a plant or a seed, I would not be able to tell whether it's sweet corn or popcorn genome, but the products are very different. (edit: thought about it some and could probably tell the seeds apart)
I do know that most South Americans and most Africans will not be growing sweet corn for my challenge. Most of them do not even seem to like sweet corn :D
...and all this is exactly why I want to see this challenge succeed - So much to learn from each other!