plain; plateau; tableland
「平ら」 has another reading with different meanings.
flat; level; even; smooth
この道は平らで歩きやすいよ。
This road is flat and easy to walk on.
テーブルを平らな場所に置いてね。
Put the table on a flat surface.
生地を平らに伸ばしてください。
Please flatten the dough.