That is because 'c' comes before 'd' in the alphabet. If two words begin with the same first letter, we then look at the second letter to decide on the alphabetical order.

The order of the alphabet became fixed soon after the letters were ... has found evidence of alphabetical ordering in Greek administrative texts as early as the second century BCE.

alphabetical order has acted as an unsung agent of democratization, providing an organizational framework based not on social hierarchies, but an easily memorized string of letters. As historian ...