"Mizu" and "Oyu" (Water and Hot Water)

In English, the word "water" is used regardless of the temperature.

However, the literal translation "atsui mizu" ("atsui" means "hot" and "mizu" means "water" in Japan) is a little unnatural.

In Japanese language, nouns that represent water change depending on the temperature.

"Mizu" often translates into "water", but if you say just "mizu", it will represent "cold water".

If you want to represent "hot water" or "boiled water", you have to say "oyu/yu" or "netto".

If you want to represent "chilled water", you have to say "reisui" or "hyosui".

By the way, "lukewarm water" is referred to as "nuruma yu", and if the water was once boiled, it's referred to as "sayu".

水とお湯

英語では、「お湯」と「水」どちらにも "water" という単語を用います。

しかし、"hot water" を直訳した「熱い水」と言う日本語は少し不自然です。

日本語では、水の温度によってその呼び方が変化します。

「水」は "water" と訳されますが、単に「水」と言うとそれは通常 "cold water" を表します。

"Hot water" や "boiled water" を表したい場合は、「お湯」や「熱湯」と言います。

"Chilled water" を表したい場合は、「冷水」や「氷水」などと言います。

ちなみに、ぬるいお湯は「ぬるま湯」、一度沸騰させてぬるくしたお湯は「白湯」と言います。