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square (of a number); multiplying (a number) by itself; second power
先生が３を二乗して黒板に書いた。
The teacher squared 3 and wrote it on the blackboard.
５の二乗は２５になります。
Five squared is twenty-five.
距離の誤差を二乗すると、精度の傾向がはっきり見える。
Squaring the distance error reveals the accuracy trend clearly.