What does the word קֹדֶשׁ (sometimes קודש), kodesh, mean?
Its form is that of a noun, like אֹכֶל or בֹּקֶר or לֹבֶן. But קדושה is a noun, and (I'm pretty sure) it means "the state/quality of being קָדֹשׁ" (arguendo, "the state/quality of being holy"), so I find it unlikely that קֹדֶשׁ means the same. If it does, then what's the difference between it and קדושה?
And if קֹדֶשׁ means "something that is holy" — which I suspect, and which would explain phrases like קֹדֶשׁ קדשים (the room or the korbanos) — then how do we understand phrases like שַׁבַּת קֹדֶשׁ (literally then "the Shabas of something holy") and וּבְדִבְרֵי קָדְשְׁךָ (literally then "in your words of something holy")?