noun
kayak
Refers to the small, narrow watercraft propelled by a double-bladed paddle. Used in both recreational and sporting contexts.
夏休みに湖でカヤックを楽しんだ。
I enjoyed kayaking on the lake during summer vacation.
彼はカヤックで川を下った。
He went down the river in a kayak.
カヌー (canoe) is a broader category; a kayak is a type of canoe, but in Japanese, カヌー often implies an open-top canoe paddled with a single-bladed paddle, while カヤック typically has a covered deck and uses a double-bladed paddle.
Borrowed from English 'kayak', ultimately from Inuktitut 'qajaq'.