Corn (5)
'corn' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for grain that I've seen before include "eg Barley" , "Cereals" , "Pattern of lines in wood" , "Enter into combat with" , "Cereal crops" .)
'corn' is the definition.
(I know that corn can be written as maize)
This is the entire clue.
(Other definitions for maize that I've seen before include "one could make a meal of it" , "Indian corn" , "Corn cob" , "Cereal grass producing corncobs" , "grain crop" .)