What overlap is there between VP of Marketing and CTO/VP of Eng?

Titles in companies don't work like military ranks with defined hierarchies and clear responsibilities. Titles mean whatever the organizations wants them to mean, overlap and collaborate as the organization requires, depending on the individuals and the situation.

One company may call their retail staff "associates," another may call them "ambasassadors." It seems like everyone with a desk at the bank has a VP title. Every "founder" puts CEO or CTO on their business card. Within the organization titles may communicate something, but in the world at large titles don't mean much.