1.
universe, cosmos
All of space and everything in it.
宇宙 covers two related meanings: the entire universe/cosmos (sense 1) and outer space beyond Earth's atmosphere (sense 2). In everyday conversation, sense 2 (outer space) is far more common.
COMMON COMPOUNDS:
- 宇宙飛行士: astronaut
- 宇宙船: spaceship
- 宇宙ステーション: space station
- 宇宙開発: space development
- 宇宙人: alien, space person
- 宇宙空間: outer space (more technical)
WORD FORMATION:
宇 + 宙 — both characters relate to vastness and space.
RELATED:
- 銀河: galaxy
- 太陽系: solar system
- 天体: celestial body