A word can not contain two letters next to each other from the same array.

I think this is ambiguously phrased. Does this mean that a word can't contain two letters, regardless of their position in the word, that are next to each other in a given array? or does it mean that the word can't have two letters neighboring each other in the word that are from the same array? For example the word EAT has E and T from array 1 and they are neighboring in the array but not in the word. Is it valid or invalid?