In a discussion of obscure references in the game Baldur’s Gate 2, I pointed out that a character named Ilyich, who had some magic acorns, was a reference to The Nutcracker Suite, by Peter Ilyich Tchaikovsky. Someone said that acorns are not nuts, but fruit, and said it’s a reference to Lenin.
nut: A hard-shelled dry fruit or seed with a separable rind or shell and interior kernel; a dry indehiscent one-seeded fruit with a woody pericarp.
So there you go. They’re both . Or to put it another way, all nuts( excluding the deranged and metallic varieties ) are fruits, but not all fruits are nuts.
It appears to me as though you can call an acorn a “fruit” if you want to, but I think people will give you funny looks. http://www.jbssinc.com/faqs.htm