late 14c., "to prostrate oneself," also "to fall flat," from flat (adj.) + -en (1). Transitive meaning "to make flat" is 1620s. Related: Flattened; flattening.
例文
1. In the squash court his chief aim is to flatten me.
壁コートでの彼の主な目標は私を負かすことです。
2.The cookies will flatten slightly while cooking.
クッキーは焼くと少し平らになります。
3. Flatten the dough with a press of the hand.
生地を手で押して平らにする。
4.If it lumpy,you can use the flatten brush to smooth along the folds.
大きなうねりがあれば、 flatten ブラシでシワに沿って滑らかにすることができます。
5.We now think prices will flatten out towards the end of this year.