後ろ
うしろ · ushiro · JLPT N5 · noun
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🔙 後ろ = 後 (after, behind) + ろ: the side that comes after you
後 is the same kanji as in 後 (ato, after) and 午後 (gogo, afternoon). What comes after in time is what lies behind in space. Sound hook: ushi (牛, cow) + ro, the cow trails at the rear of the herd.