なぜルーンって呼ばれてるの？

why; how

roux (mixture of butter and flour used to make sauces); sauce made from such a mixture; (Japanese) curry powder; curry sauce made from this powder

some (at the start of a number in place of a digit)

casual quoting particle; indicates supposition; if ... then; indicates a rhetorical question; indicates certainty, insistence, etc.

to call out (to); to call; to invoke; to summon (a doctor, etc.); to invite; to designate; to name; to brand; to garner (support, etc.); to gather; to take as one's wife

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question