水蒸気（すいじょうき、suijouki）
- water vapor

The Japanese word 水蒸気 (すいじょうき) refers to water vapor, which is water in its gaseous state. ⚫︎ It is formed when water evaporates, meaning it changes from a liquid to a gas due to heat. ⚫︎ 水蒸気 is invisible, unlike clouds which are made up of tiny water droplets or ice crystals. ⚫︎ It's a key component of the water cycle and plays a crucial role in weather phenomena. ⚫︎ This 水蒸気 can condense back into liquid water, forming rain, dew, or fog.

⚫︎お風呂から水蒸気が立ち上っている。 Translation: Steam is rising from the bath. ⚫︎鍋から水蒸気が出て、部屋が曇ってきた。 Translation: Steam is coming from the pot, and the room has become foggy. ⚫︎空にはたくさんの水蒸気が含まれている。 Translation: The sky contains a lot of water vapor.

⚫︎ You would use 水蒸気 when talking about steam, vapor, or the gaseous form of water. ⚫︎ It can be used in scientific contexts, everyday conversations about cooking or bathing, and discussions about the weather. ⚫︎ It's a relatively formal term, and appropriate in most situations, although more casual terms might be used in some conversations (e.g. "steam" instead of "water vapor").

⚫︎ The word is written as 水蒸気 in kanji. ⚫︎ The reading is すいじょうき in hiragana. ⚫︎ There is no katakana version. ⚫︎ The kanji are standard, so there are no variations in how it is written. ⚫︎ The okurigana (送りがな, the hiragana attached to kanji) is consistent.

There are no direct synonyms in Japanese that specifically mean "water vapor." ⚫︎ However, related words or phrases could include: ⚫︎ 蒸気 (じょうき) - steam (which is often close to 水蒸気 in meaning) ⚫︎ 湯気 (ゆげ) - steam, vapor (specifically from hot water) ⚫︎ 気体 (きたい) - gas (broader term, including 水蒸気 as a type of gas)

The direct antonym of 水蒸気 would be the liquid form of water, 水 (みず). ⚫︎ While not a perfect antonym, words representing other states of water can also be considered: ⚫︎ 氷 (こおり) - ice (solid state)

熱いコーヒーから水蒸気が立ちのぼった。 ・Translation: Steam rose from the hot coffee. ・Explanation: This sentence describes the visible steam emanating from hot coffee, emphasizing the presence of 水蒸気.

水蒸気は空気中に含まれており、雲を形成する。 ・Translation: Water vapor is contained in the air and forms clouds. ・Explanation: This sentence explains the role of 水蒸気 in the formation of clouds, linking it to a natural phenomenon.

⚫︎ The word 水蒸気 is formed from three kanji: ⚫︎ 水 (みず) - water ⚫︎ 蒸 (じょう) - steam, to evaporate ⚫︎ 気 (き) - vapor, air, gas ⚫︎ It literally translates to "water steam vapor" or "water steam gas," describing the gaseous state of water.