canteen

面白いと聞いたので、HOLES by Louis Sacharを読むことにしました。罪を犯した少年の矯正所での話なので、多分中学生あるいは小学生の高学年向けだと思います。　濡れ衣で矯正所に送られた主人公 Stanleyが矯正所に着いて支給された物の中に "canteen" がありました。
　 He was also given white sneakers, an orange cap, and a canteen made of heavy plastic, whcih unfortunately was empty.
私の知っている "canteen" は会社や学校の食堂、あるいは酒を飲む場所でしたが、上の "canteen" は明らかに別物です。　しかし、この単語は次ぎの例のようにこの後も何度も出てくるので意味は辞書を引かなくても分かります。
"Hey, uh, Theodore," he said, going after him. "Do you know where I can fill my canteen?" 一応辞書の説明を確認します。
・Cambridge English Dictionary: a small container for carrying water or another drink, used especially by soldiers or travellers
・Vocabulary.com:　A canteen is a store that sells food and drink at an institution like a camp, college, or military base. A canteen can also be a small container used to carry water to drink.
If you’re at summer camp, you can buy snacks at the canteen. This kind of canteen is a little shop. At the canteen, you can buy little things like potato chips or a can opener. A canteen is like a convenience store. The other kind of canteen is good if you’re going on a hike -- fill it up with water and put it in your backpack, since there probably aren’t any of those other kinds of canteens out in the woods.