多い
おおい · ooi · JLPT N5 · i-adj
many
oh-oh-EE: so many that one oh is not enough, you need two
多 is the kanji 夕 (evening) written twice, one stacked on the other: a thing repeated means many. The reading doubles too, with a long oo before the final i. Doubled shape, doubled vowel, large quantity.
多 — two 夕 (evening) stacked
多 originally depicted two pieces of meat (夕, a variant of 肉) stacked together, suggesting abundance. Over time it was reanalyzed as two 'evenings' piled up — many evenings meaning many days, hence 'many, much'. The doubling itself conveys quantity.