Corn has husk, silk and kernels. In the middle there is the cob, which only becomes visible after you have eaten the kernels. 

[![enter image description here][1]][1]

The **husk** is, botanically speaking, formed of leaves, but it has a different texture from the standard leaves and encloses the cob with the kernels snugly. It can be left on the cob during boiling, or removed before boiling. For grilling and other preparations, remove the husk. It is not edible, historically it was used for crafting. In the kitchen, it can be used for wrapping a tamale, although wider leaflike matter is more convenient, if available (such as banana leaves). 

The **silk** is called that because it looks and feels like silk while young. The silk in ripe corn tends to be sun dried and brittle, at least outside of the "package" of husk. It is not usually eaten. See also http://cooking.stackexchange.com/questions/4349/tips-for-removing-silk-from-corn?rq=1. 

The **kernels** are what you want to eat. Most methods call for preparing them while still on the cob. If you need them removed, you can "shave them off" the cob with a sharp knife. 

The **cob** itself is the dry semihard thing in the center. It has no culinary uses. 

The **leaves** are used to feed livestock, but not eaten by humans. 

An **ear** is the name for the whole package you pick off the plant, so the kernels on the cob with their silk and husk. 

  [1]: https://i.sstatic.net/yw3dR.png