Are all billionaires also millionaires? In other words, should the definition of millionaire be taken to include billionaires, or exclude them?

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    Please add dictionary definitions, 107, linked and attributed. // Would you say "He's a millionaire ... perhaps even a billionaire" is incorrect? Feb 26, 2020 at 17:52
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    Would you say that an octogenarian is also a septuagenarian_ ?
    – Nigel J
    Feb 26, 2020 at 18:13
  • @Nigel J Would most people say that a square is a rectangle? That a shrimp and a prawn are similar? When precising definitions may well be involved, one has to define terms, not assume a particular definition. Feb 26, 2020 at 18:47
  • What does the dictionary say? The definition I looked at didn't place an upper limit on a millionaire's wealth.
    – nnnnnn
    Feb 27, 2020 at 1:41
  • It was not a good decision to close this question.
    – Greg Lee
    Feb 27, 2020 at 11:32

2 Answers 2


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")

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    Billionaires wouldn't normally be called millionaires, but they'd probably be included in an accurate count of "total millionaires" unless that counting exercise involved producing a separate tally for "total billionaires". Feb 26, 2020 at 18:36
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    @FF The maxim of adapting to the register being used. To most people, squares aren't rectangles. Feb 26, 2020 at 18:45
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    I went to an LCC junior school in London from 1959, where I was taught the difference between a rectangle and an oblong. Feb 26, 2020 at 18:53
  • @EdwinAshworth - Anyone with a basic highschool education should know that squares are rectangles mathematically, but in non-maths contexts I believe you're right that most people would assume that references to "rectangles" would not include squares. (So in other words the answer is "maybe"?)
    – nnnnnn
    Feb 27, 2020 at 1:39
  • @nnnnnn No; the answer is to either agree (defining if necessary) or fully understand the prevailing usage in the situation in which you're conversing, or (if you're lecturing, writing a book ...) explain your terminology. Then stick to it for the duration. The answer is not 'maybe', but 'yes' or 'no'. But we can't say which until the context is spelled out. Feb 27, 2020 at 12:37

It is a distinction that is made and should be made. To do otherwise is to deceive.

To say that Michael Bloomberg is a millionaire when he actually has a net worth over 50 billion dollars is such a misrepresentation that it would probably be considered a lie.

Also being a billionaire means you have passed a threshold.


According to the 2018 Sunday Times Rich List, Rowling's net worth is estimated at around 700 million. She famously lost her billionaire status, due to the amount of money she's donated to charity.

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