水筒（すいとう、suitou）
- water bottle

The Japanese word 水筒 (水筒, suito) refers to a water bottle or a canteen. It's a container designed to carry liquids, typically water, for later consumption. These can be made from various materials like plastic, metal (stainless steel), or glass and are often designed to be portable and reusable. The main purpose of a 水筒 is to keep liquids accessible for drinking while on the go or when away from a convenient water source.

⚫︎ 学校に 水筒 を持って行く。 Translation: I take a water bottle to school. ⚫︎ 暑いから、 水筒 に水を入れてください。 Translation: It's hot, so please fill the water bottle with water. ⚫︎ 新しい 水筒 はどこで買いましたか？ Translation: Where did you buy your new water bottle?

You use the word 水筒 in situations where you are referring to a water bottle or canteen. ⚫︎When talking about bringing a water bottle with you. ⚫︎When discussing the contents of a water bottle (like water, tea, or juice). ⚫︎When talking about the type or material of the water bottle. ⚫︎It's common to use 水筒 when describing actions involving carrying, filling, or drinking from a water bottle.

The word 水筒 is typically written with: ⚫︎ Kanji: 水筒 ⚫︎ Hiragana (reading): すいとう There are no common variations in how it is written. The okurigana is fixed.

⚫︎ There aren't many direct synonyms for 水筒 in Japanese, as it is a specific object. However, depending on context, you could use more general terms. ⚫︎ For instance, "bottle" (ボトル, botoru) might sometimes be used, though it is a more general term. ⚫︎ "Canteen" (which can be a direct English translation) is less commonly used in modern Japanese.

There aren't specific antonyms in the same way as words like "hot" and "cold." The concept doesn't really have an opposite, as 水筒 refers to a physical object.

夏は、いつも 水筒 にお茶を入れて持ち歩きます。 ・Translation: In summer, I always put tea in my water bottle and carry it around. ・Explanation: This sentence explains the practical use of a 水筒 in everyday life, especially during warmer months.

この 水筒 は保冷機能があって、冷たい飲み物を長時間保てます。 ・Translation: This water bottle has a cooling function and can keep cold drinks for a long time. ・Explanation: This explains a feature of the 水筒, its ability to keep drinks cold.

⚫︎ 水 (sui) means "water." ⚫︎ 筒 (tō) means "tube," "pipe," or "cylinder." ⚫︎ Therefore, the word 水筒 literally translates to "water cylinder" or "water tube," reflecting the container's function of holding water.