宙
チュウ, ひろ, ゆ

mid-air, air, space, sky, memorization, interval of time

JLPT1 G6 S8 F1005

As per 由# (pass/run through) + 宀 roof/building → *the heavens*, likened to an arch passing through the sky (compare 宇) → *space*; *the air*.

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