Watching planes take off and land as a young child in the early 70s, we called the following planes "jumbo jets"
This from my grandfather, who was a career Lockheed man. Perhaps the Lockheed employees used it euphamistically.
Now when the 767 came out, we called it a "widebody" because that's what Boeing and the airlines called it at the time.
I never had much of an opinion on the A300, because I never saw them and didn't know much about them, really until I rode on a CO
A300 in 1994. I know i did not refer to it as a jumbo, but i remember thinking it was DC-10 sized, at that time. There really wasn't that much information on Airbus until more recent times, with the advent of the Internet and the appearance of many more Airbii in the USA.
Firings, if well done, are good for employee morale.