底面(ていめん)

ていめん
noun
bottom surface; base; underside
descriptive
1. bottom surface; base; underside
The lowest surface of an object, container, or geometric shape. Used both in everyday contexts (the bottom of a box) and in mathematics (the base of a solid figure).
箱(はこ)の底面(ていめん)に名前(なまえ)を書(か)く。
To write one's name on the bottom of the box.
底面(ていめん)の面積(めんせき)を求(もと)めなさい。
Calculate the area of the base.
この円柱(えんちゅう)の底面(ていめん)は半径(はんけい)五(ご)センチの円(えん)である。
The base of this cylinder is a circle with a radius of five centimeters.

Composed of 底(てい) (bottom) and 面(めん) (surface, face). Used in both everyday and mathematical/technical contexts.

Common collocations

  • 底面(ていめん)の面積(めんせき): area of the base
  • 底面(ていめん)積(せき): base area
  • 底面(ていめん)が平(たい)ら: the bottom is flat
  • 底面(ていめん)に滑(す)り止(ど)め: non-slip on the bottom

Similar words

  • 底(そこ): bottom — more casual and general; the bottom of a bag, ocean, etc.
  • 裏面(りめん): reverse side / back — the opposite side of a flat object, not necessarily the bottom
  • 下面(かめん): lower surface — the underside, similar but less common

Usage

In mathematics, 底面(ていめん) specifically refers to the base of a three-dimensional figure such as a prism, cylinder, or pyramid. This is a common term in Japanese math education.

Related Words

Compare: 裏面(りめん) (reverse side / back)
general
Added 2026.4.5 6:14 · Revised 2026.9.12 13:58
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