正方形|せいほうけいseihoukei[0]heiban (flat)

1. no-adjectivesquare
   正方形せいほうけいは４つの同おなじ長ながさの辺へんをもつ。↗

   A square has four equal sides.

• Synonym真四角ましかくCasualColloquial. A neat, four-square shape; more casual than 「正方形」.
• Synonym正方せいほうWrittenWritten/formal prose. Means a square or square shape, but mostly appears in compounds; rarely used on its own.
• Synonymまっ四角まっしかくCasualColloquial. Perfectly square; a more emphatic version of 「真四角」.

For a geometric square, use 「正方形」. In casual speech, 「真四角」 or the more emphatic 「まっ四角」 fits; 「正方」 is written prose and mostly appears in compounds.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 全すべての角かどが直角ちょっかくで、全すべての辺へんの長ながさが等ひとしい四よん角形かくけい。