HSK 6 HSK V7-9
Correct

平面

/ píngmiàn / 
Strokes

Definition

plane (flat surface)/print media

Example

As a Noun

plane

1
Shuǐpíngmiàn
水平面

horizontal plane

2
Chuízhí
垂直
píngmiàn
平面

vertical plane

As a Noun

level

3
Hǎipíngmiàn
海平面

sea level