How to say "hemisphere" in Japanese

• 半球はんきゅうCommon
  nounThe common word for a hemisphere as an object or region: half of a sphere, such as one of the Earth's halves or one of the brain's. Choose this in most contexts.
  赤道せきどうは地球ちきゅうを二ふたつの半球はんきゅうに分わける。↗

  The equator divides the globe into two hemispheres.
• 半球形はんきゅうけい
  no-adjectivePoints to the shape itself — a dome-like, hemispherical form. It is seldom the word you want for a hemisphere as a region, such as the Earth's or the brain's; use 半球 there.

Use 半球, the common word, for a hemisphere itself — half a sphere, the Earth's halves, the brain's — and the less common 半球形 when you mean a dome-like, hemispherical shape.

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

• 半球はんきゅうhemisphere
• 半球形はんきゅうけいhemisphere