同どう一いつ平へい面めん上じょう

noun which may take the genitive case particle 'no'

coplanar; in the same plane; flush; even with

Technical term used in geometry, engineering, and design to describe objects lying in the same plane or surfaces that are level with each other. Often appears as 同一平面上に.

• これらの点てんは同どう一いつ平へい面めん上じょうにある。

  These points are coplanar.

• 棚たなの表ひょう面めんを壁かべと同どう一いつ平へい面めん上じょうに設せっ置ちする。

  Install the shelf surface flush with the wall.