Recently I saw a post on the meta.rpg.se site that asked When is editing your answer not kosher?, and it got me thinking. Why is the word Kosher used, instead of, for example, Halal, Permissible, or even just Okay? They would all have the same meaning, more or less. When did kosher first enter the English language, and how has it been popularised to being used in the context above?
The definition on Etymonline is:
"ritually fit or pure" (especially of food), 1851, from Yiddish kosher, from Heb. kasher "fit, proper, lawful," from base of kasher "was suitable, proper." Generalized sense of "correct, legitimate" is from 1896.
It seems a fair leap from 'ritually fit or pure' to the common usage, which almost connotes something being 'socially' acceptable as opposed to 'religiously' acceptable or even acceptable by fixed standards (in contrast to the freeform 'social' standards).
Can anyone help me here?