Are all billionaires also millionaires? [closed]

Solution 1:

No, billionaires are not called "millionaires", even though by definition they may actually be millionaires. The relevant conversational principle is the maxim of quantity:

Grice's Maxims. The maxim of quantity, where one tries to be as informative as one possibly can, and gives as much information as is needed, and no more. ... The maxim of manner, when one tries to be as clear, as brief, and as orderly as one can in what one says, and where one avoids obscurity and ambiguity.

(by googling "maxim of quantity")