The Meaning of wakusei [惑星] In Japanese

惑星
わくせい
Romaji: wakusei N5

What does 惑星 mean?

Translation and Meaning

planet, celestial body

Definition

惑星 means ‘planet’ in Japanese, referring to a major celestial body that orbits a star. In astronomy, planets are objects large enough to be rounded by their own gravity and that have cleared their orbital path, covering planets within and beyond our solar system.

Type

Noun (名詞)

Stroke Order

Meanings

  • planet in astronomy — wakusei
  • Earth-like and other planetary types appear in scientific discourse — wakusei
  • in education, used to discuss solar system structure and exoplanets — wakusei

Etymology

wakusei is built from the on’yomi readings of 惑 and 星, pairing a verb-like notion of confusion with the star element to form a formal compound used in Sino-Japanese scientific terminology.

Origin

Adopted from Classical Chinese scientific vocabulary, with the Japanese usage appearing in early modern astronomy texts and later standardizing in Edo-period dictionaries and science literature.

Composition

  • 惑: bewilder, perplex
  • 星: star
  • 惑星: the concept of a wanderer among the stars, i.e., a planet

Usage

Used in formal scientific writing, educational textbooks, and astronomy discussions to denote a planet. It appears in phrases describing planetary features, orbital dynamics, and exoplanet research; casual speech may replace it with 地球 in Earth-specific contexts.
💡 Tips
Mnemonic: wakusei sounds like ‘wander-star’—remember planets are the wanderers among the fixed stars.

Variations

  • 天体 (tentai) — celestial body
  • 恒星 (kousei) — star
  • 地球 (Chikyū) — Earth

Example Phrases

  • 今夜、惑星がきれいに見えるね。
    Kon’ya, wakusei ga kirei ni mieru ne.
    Tonight, the planets look beautiful.
    Lista:
    • 今夜 (kon’ya) – tonight
    • 惑星 (wakusei) – planet
    • が (ga) – subject marker
    • きれいに (kirei ni) – beautifully
    • 見える (mieru) – to be seen / look
    • ね (ne) – right?
    Neste exemplo, 「惑星」 funciona como o sujeito, marcado pela partícula が; usa-se 見える para indicar que é visível no céu.
惑星