According to USA Pickleball, pickleball got its name from the sport of rowing. In crew races, a "pickle boat is made up of rowers who are left over from other boats. Pickleball was invented on Bainbridge Island, Washington, where there's a rowing club.
The creators of pickleball (Joel Pritchard, Bill Bell, and Barney McCallum) invented it from the spare parts of other sports: a badminton court, ping-pong paddles, and a wiffle ball. Hence the link between a pickle boat and pickleball!