Well, maybe more research required. However, I recall seing them referred to in Canberra F700s as "Rumbold" seats, so if it's not right, at least it is an officially recognised error.
Conceivable, I guess, that Mr Rumbold designed the original one for cars, these were corrupted to "Rumble" early on and the word passed on into aircraft seats.
Yes, I do have a life - but I'm easily distracted by obscure origins...!