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lower reaches (of a river)
bottom; lower part
lower half (of the body, esp. the privates); feces (faeces); urine; menses
end; far from the imperial palace (i.e. far from Kyoto, esp. of western Japan)
dirty (e.g. dirty jokes, etc.)
「下」 has other readings with different meanings.
川の下の方に橋がある。
There's a bridge downstream.
忠実なしもべとして仕えた。
I served as a faithful servant.
上から下まで全部読み直した。
I reread everything from top to bottom.