The usage of "of"

[sky3120]

I have learned that A is equal to B in A of B structure such as the City of London, and at the age of 52, but I heard that the word of A and the expression of A should be rewritten to the word, 'A' and the expression, 'A'. So A of B structure implying equals is not correct or optional or is there more I should know about the structure? I really appreciate your help and pointing out.

[5jj]

I have changed your question to make it slightly easier to understand, sky:

I have learned that A is equal to B in an "A of B" structure such as "City of London", but I heard that "the word of A "and "the expression of A" should be rewritten to as "the word, 'A'" and "the expression, 'A'" . So to say that an "A of B" structure implyingies equals is not correct or optional, or is there more I should know about the structure?.