球(きゅう)

きゅう
noun
sphere; ball (geometric)
number
1. sphere; ball (geometric)
A sphere in the geometric sense — a perfectly round three-dimensional shape. Used in math, science, and the names of round objects. Distinct from ボール, which refers to balls used in sports.
球(きゅう)の体積(たいせき)を計算(けいさん)する。
Calculate the volume of a sphere.
地球(ちきゅう)は完全(かんぜん)な球(きゅう)ではない。
The Earth is not a perfect sphere.
半径(はんけい)が倍(ばい)になると、球(きゅう)の表面積(ひょうめんせき)は四倍(よんばい)になる。
When the radius doubles, the surface area of a sphere becomes four times larger.

Single-character noun used in geometry and as the building block of many compounds. In ordinary speech a round object is more often ボール (sports ball) or 玉(たま) (small round thing).

Compounds

Similar words

  • ボール: ball (sports, toys) — everyday word for a ball you can throw or kick
  • 玉(たま): bead; small ball; bullet — everyday small round things

Related Words

Compare: ボール (ball)
Compare: 玉(たま) (bead)
Related: 円筒(えんとう) (cylinder)
general
Added 2026.6.7 11:04 · Revised 2026.9.2 13:02
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