Passover.

So can this go in Holidays & Traditions?

Yes. The Judaism category, plus Holidays & Traditions.

How about creating it in the Holidays & Traditions and a weaved link/interlink in the Judaism category page?

I think sharing it on both is better.

http://www.wikihow.com/Category:Passover Because it is a holiday, it’s categorized in the Holidays and Traditions. The word “Jewish” is an adjective. If it was solely & specifically pertaining to the religion itself, then I could see it being actually categorized in that. Same rule applies for any other religious holiday - Christmas isn’t double categorized with Christianity.

Well, I think it should be double categorized with Judaism, because it is a major Jewish holiday. Christianity already has Catholicism, Mormonism, & Bibles as its subcategories, so no need to add Christmas or Easter to the mix.

Adding Judaism is exactly the same if you were to add Christianity to Christmas. Christmas is a (major) Christian holiday. Passover is a (major) Jewish holiday. The religions are just adjectives. There is no reason to double categorize holidays with religions. On the same lines as your defence, let’s add Halloween to witchcraft.