雑炊

ぞうすい rice porridge made by simmering cooked rice in a seasoned broth, often containing vegetables, fish, etc. (usu. made from leftovers)

Why it means this

雑 (miscellaneous) + 炊 (cook) — a rice soup simmered with vegetables and bits of fish, often made from leftovers or the dregs of a hot pot.

Breakdown

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