I see the word used in reference to food, satisfaction, safe, etc. All I know about the word is that the Jewish community loves to use it. What does it mean and how is used?
Its original meaning is to signify what food Jews are allowed to eat, and how the food must be prepared. But it has morphed into meaning “what is allowed” or “what is acceptable” in any area.
Pork is not Kosher. (original meaning)
Farting in public is not kosher. (modern, expanded meaning).
In general, for a meat animal to be kosher it has to come from an animal that chews its cud and has a cloven hoof. It also needs to be killed in a prescribed method, draining the blood and avoiding undue suffering. I think that birds are kosher as long as they’re killed properly. Seafood is only kosher if it swims and has scales (leaving out lobster and shark, for some).
In addition, you’re not supposed to mix milk and meat in the same meal (or even mix utensils used for both – a kosher home has two sets of dishes, plus Passover dishes, since you can’t use anything that’s touched bread for Passover). In general, vegetables and fruit are always kosher.
An observant Jew is supposed to keep kosher and eat only kosher food.
The literal meaning is “fit” or “appropriate” or “acceptable.” As John Mace says, it is mostly used in terms of foods, based on Jewish dietary restrictions, but has been more widely used.
For a summary of the rules that make food kosher, the following gives an overview (comparing to Islamic dietary rules, but still):
Straight Dope Staff Report: Do Jewish and Islamic dietary laws have anything in common?
A search on “kosher” in the Straight Dope Archives would also find the following:
What do K, R, and U means on food and other packages?
Thanks guys.