Most of us know this as a trampoline. Our three year old calls it a "jumping machine." We were having morning tea at a friend's house this morning and it was rather amusing listening to her telling her little friend whose turn it was to go on the jumping machine.
I did correct her a couple of times. And then I just thought, well, it's cute. And she'll work out what it's really called sooner or later anyway. Until then, it can be one of those cute toddler things to remember later. Hence this post, since I'm pretty sure I won't remember to write it down anywhere else.