底てい面めん

noun

bottom; underside; base

General term for the bottom surface of an object, such as a container, device, or structure.

• 箱はこの底てい面めんに製せい造ぞう年ねん月がっ日ぴが印いん刷さつされている。

  The date of manufacture is printed on the bottom of the box.

• 底てい面めんが滑すべりにくい素そ材ざいでできている。

  The underside is made of a non-slip material.

noun

base (of a polyhedron)

In geometry, the face on which a solid figure is thought to rest; often used for prisms, pyramids, etc.

• 三さん角かく柱ちゅうの底てい面めんは三さん角かく形けいである。

  The base of a triangular prism is a triangle.