I was reading an article that uses the phrase "Achilles' heel" to refer to Facebook's acquisition of Instagram, but it was written thus:
achilles heel
My main question is – was this a bad mistake or is making this kind of description in this way a common thing? If so, could you provide examples where others have taken common phrases and lowercased them.
A little more context in case it helps:
Because Facebook is essentially about photos, and Instagram had found and attacked Facebook’s achilles heel — mobile photo sharing.
Best Answer
Achilles is a proper noun. However, this ngram does seem to show some extremely slight/rare incidence of the lowercase form.
That doesn’t make it “right” or generally accepted.