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plain; plateau; tableland
「平ら」 has another reading with different meanings.
flat; level; even; smooth
この道みちは平らたいらで歩きあるきやすいよ。
This road is flat and easy to walk on.
テーブルを平らたいらな場所ばしょに置いおいてね。
Put the table on a flat surface.
生地きじを平らたいらに伸ばしのばしてください。
Please flatten the dough.