Flat; level; even — describing a surface or shape that is nearly plane with little elevation difference.
平たい皿に料理を盛ると見栄えが良い。
Dishes look better served on a flat plate.
あの山の道は比較的平たくて歩きやすい。
That mountain path is relatively flat and easy to walk on.
この石は表面が平たく削られている。
This stone has been carved flat on the surface.
Plain or simple (language, explanation); expressed in straightforward, easy-to-understand terms (often used in phrases like '平たく言えば').
平たく言えば、それはお金の貸し借りに関する問題です。
Put simply, it's a matter of lending and borrowing money.
専門用語を使わずに平たく説明してください。
Please explain it plainly without using technical terms.
彼女は複雑な事情を平たくまとめて話した。
She summed up the complicated situation in simple terms.