1Water — the everyday liquid for drinking, cooking, washing, etc. In Japanese, 水 (read みず) specifically refers to cool or room-temperature water, in contrast to お湯 (hot water).
すみません、お水を一杯ください。
Excuse me, could I have a glass of water?
のどが渇いたから、冷たい水を飲んだ。
I was thirsty, so I drank some cold water.
お湯ではなく、水で顔を洗ってください。
Wash your face with cold water, not hot water.
毎朝、起きたらまず水を一杯飲むようにしている。
Every morning when I wake up, I make a point of drinking a glass of water first.
この川の水はとてもきれいだ。
The water in this river is very clean.
2A general term for fluid or liquid — often referring to bodily fluids, plant moisture, or water-like liquids that have collected somewhere.
ひざに水がたまって、歩くと痛い。
Fluid has built up in my knee, and it hurts when I walk.
植物は根から水を吸い上げて葉まで運ぶ。
Plants draw water up through their roots and carry it to the leaves.
やけどのあとに水ぶくれができてしまった。
A blister formed after the burn.
3Floodwater — the water of a flood or inundation, especially when it threatens or damages homes and land.
大雨で川があふれ、家の中まで水が入ってきた。
Heavy rain made the river overflow, and water came right into the house.
水が引くまで避難所で待つしかない。
We have no choice but to wait at the shelter until the floodwaters recede.
4In sumo, the water given to a wrestler to rinse out his mouth just before a bout. Formally called 力水 (chikara-mizu, 'power water').
力士は土俵に上がる前に水をつけた。
The wrestler took the ritual water before stepping into the ring.
5In sumo, a brief pause called by the referee when a bout drags on without a clear winner. Known as 水入り (mizu-iri); the wrestlers reset and resume.
大一番が長引き、ついに水が入った。
The marquee bout dragged on, and finally a water-break was called.