Which is correct?
a. one and the same
b. one in the same
The expression is “one and the same.” It uses reiteration for emphasis. Peter Parker and Spiderman, for example: They are one and they are the same. Which is problematic if they’re invited to the same cocktail party: Two invitations, one dude.
I have to admit, I was shocked — shocked! — by how many people get this one wrong. Drum roll, please …
One and the same: 245,000,000 results
One in the same: 1,920,000,000 results
I blame this, as usual, on so many more people writing than reading. Those non-reading writers hear an expression but don’t see it in print and so they don’t understand what they’re hearing. A lot of the people using the expression “one in the same” online are wondering what it means. Well, no wonder — it doesn’t mean anything at all!
Paul Brians includes “one in the same” in his Common Errors in English Usage.
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