noun
same plane; same level
Refers to objects or points lying on the same geometric plane or at the same height. Common in technical, mathematical, or architectural contexts.
これらの点はすべて同一平面上にある。
These points all lie on the same plane.
二つの線が同一平面に存在するか確認してください。
Please check whether the two lines exist on the same plane.
noun which may take the genitive case particle 'no'
Describes surfaces that are perfectly level with each other, with no gap or step. Often used in construction, carpentry, or design.
この棚は壁と同一平面になるように取り付けてください。
Please install this shelf so that it is flush with the wall.
床と同一平面の引き戸を採用した
We adopted a sliding door that is flush with the floor.
Compound of 同一 (same, identical) and 平面 (plane, level surface). The term is a straightforward technical expression with no irregular etymology.