底|そこsoko[0]heiban (flat)

1. nounbottom; sole
   靴くつの底そこがすり減へってしまった。↗

   The soles of my shoes are worn.

• SynonymボトムNeutralA loanword for the bottom of something, or for lower garments like trousers and skirts (「ボトムス」). Also the lowest point of market prices.
• Synonym下側したがわNeutralThe lower side of something, as in 「下側に置く」. Common in speech, and leans toward describing position.
• Synonym基底きていWrittenA written word for a foundation or the base surface of a solid; mostly academic (e.g. mathematics). Not the everyday word for a container's bottom.
• Synonym底面ていめんWrittenThe bottom face of a solid or container, as in 「円柱の底面」. A mathematical, technical term; not the everyday word for the bottom of things.
• Synonym底部ていぶNeutralThe bottom part of something, as in 「容器の底部」. Leans toward written, explanatory prose; 「底」 is the more everyday choice.
• Related底辺ていへんNeutralThe base of a triangle, or the bottom rung of society, as in 「社会の底辺」. Does not refer to the bottom of a container.
• Related尻しりNeutralLiterally the buttocks, but also the bottom of an object or the end of a line, as in 「鍋の尻」「列の尻」. Colloquial in tone.
• Related下方かほうWrittenThe area or direction below, as in 「下方修正」. It expresses a direction or region, not the bottom part of a thing as such.
• Related下部かぶNeutralThe lower part of an object, as in 「建物の下部」. Covers a wider range than 「底」, taking in the whole lower section rather than only the lowest part.
• Related麓ふもとNeutralThe foot of a mountain, as in 「富士山の麓」. Restricted to mountains; use 「底」 for other low points.
• Related基部きぶWrittenThe base or root section of something, as in 「首の基部」. Found mostly in anatomy and architecture; written/formal prose.
• Related根元ねもとNeutralThe root of a plant or the base where something is fixed, as in 「木の根元」. About where things grow or are anchored, not the bottom of a container.
• Related下面かめんWrittenA written word for the face of an object that points downward, mostly in technical descriptions. Not the everyday 「底」.
• Antonym上端じょうたんNeutralThe upper end or top edge of something — the opposite of 「底」, the lowest part.
• Antonym頂上ちょうじょうNeutralThe summit or highest point, as of a mountain — the opposite of 「底」, the lowest point.

Use 「底」 for the bottom of a container or of terrain — the everyday default. In formal or technical prose pick 「底部」 or 「底面」 (a geometric base); 「根元」 for plant roots, 「麓」 for a mountain's foot, 「尻」 colloquially for an object's bottom or end of a line. 「下部」 covers the broader lower section, 「下方」 a direction; 「ボトム」 also means lower garments. Opposites: 「上端」, 「頂上」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. （そこ）器うつわ、図形ずけい、地形ちけいなど、物体ぶったいの最もっとも下したになる部分ぶぶん。即すなわち、ある部分ぶぶんの周囲しゅういが全すべて、その部分ぶぶんよりも高たかい位置いちをなしている場合ばあいのある部分ぶぶん。