When people say there’s been an “𝑥 fold increase in such and such.” They mean such and such is 𝑥 times as big.
If you get something that actually folds like a sheet of paper, the amount of layers doubles each time. One fold = twice as many layers. Two folds = four times as many layers…
Yeah, 'number’fold words in modern English are actually linguistic hold overs from before ‘fold’ was a verb that meant to bend something along a crease.
https://www.etymonline.com/word/twofold
In a whole bunch of proto-English languages, fold or feald or fald or falt were all multiplicative suffixes (basically) attached to a number, which made a new word meaning to multiply by the number.
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I’d be willing to bet this is also why the phrase ‘doubled over’ literally means that a person is bent, or folded at their abdomen.
You take the new meaning of fold (to bend along a crease) but replace it with the word that twofold literally means (doubled).
If you interpreted ‘doubled over’ as literally as OP is taking twofold, then the phrase should mean that a person was above something and then spontaneously grew a clone of themselves, or became twice as heavy or tall or something.
This is actually pretty interesting. I wish I could pin someone else’s comment. Thanks.
NP! =D
It took me way too long to realise you weren’t asserting an unorthodox answer to the nondeterministic polynomial time problem.