Where did the word “kosher” come from? I know what it means but the word isn’t in the Bible.?

The word is Hebrew; it just means “fit for ritual use.” It and the noun form, kashrut, come from the Hebrew root word spelled Kaf-Shin-Resh (sort of KSR – Hebrew doesn’t use vowels), meaning fit, proper, or correct. Kashrut is the entire compilation or system of dietary laws, rather than any one law in the Torah. Kashrut and kosher can also apply to anything used in Jewish ritual; for instance, a “kosher” menorah for Hanukkah has to have 9 branches, 8 of which are at the same level, and the ninth one being the “servant” candle holder (or oil cup), which should be slightly higher. If the 8 branches are at different levels, it’s pretty, but it’s not strictly “kosher.”

The word Kosher comes from the Hebrew כשר. Its only usage in the Bible is in Esther 8:5 and in that context means “fitting” (but not in terms of food). It later is applied mostly in the context of whether a particular food is fitting (as in appropriate or allowed) to be eaten.

In modern Judaism, “kosher” denotes that the food fits certain parameters in terms of what it is (not pig, shellfish etc.) how it was slaughtered (by a Jewish trained slaughterer and by a certain method), and how it was prepared (not mixing milk and meat, etc.)

It also means “fitting” as if whether a certain action is legitimate and in this sense it has made its way into modern English. So for example: “Is this a kosher deal” meaning is the deal as it should be.