大気
たいき · taiki · JLPT N3 · noun
atmosphere
🌍💨 大気 = big (大) + air (気): the big air around the Earth
気 (ki) means air, breath or spirit, as in 空気 (kūki, air) and 天気 (tenki, weather). Add 大 (tai, big) and you get the large mass of air surrounding the planet, the atmosphere.
大 — pictograph of a person with arms outstretched
大 is a pictograph showing a person standing with arms and legs spread wide. The outstretched arms suggest 'big' or 'great', extending from the literal image of a large stance to abstract meanings like important or grand. It is one of the oldest characters, found on oracle bones.