"Yak" is a good "Y" word, but the picture isn't an animal. But if somebody in a factory in China said "yaks", somebody else heard "yax" morphing to "ax" or "yxa" (the Swedish word), I can see how they would have ended up printing that on the ball, maybe.

I wouldn't have thought of "yacht". Maybe "yo-yo" (that came up in the linked post), or "yarn" (ball or skein of).