That's true, but their meanings change. They change because people choose to use words in new ways. If enough people use the word in the new manner then the new meaning gets put in the dictionary.
There is no arbiter to decide whether the new use is "good" or "bad", "proper" or "improper". Change just happens.
The original boat, the one to which you objected, is a super-wide and short sit-on-top "kayak" for want of a better word. It's quite different from a sea kayak or a white water boat and no one who has seen examples of each is going to confuse them. Relax.
Touring Kayak Paddles
|Table of Contents|