I don't understand how to do this problem.

I need to figure out how many different 14 letter words I can form with 5 A's, 3 B's, and 6 C's. I understand that since some letters are the same the words would be indistinguishable if it was just 14 factorial. But why would I only divide that number by (5 x 3 x 6)? Can you help me understand this concept of combinations vs. permutations?