It was originally the name of a certain kind of meat, although the ‘dubious quality’ part is well-enshrined in urban legend – known backronyms devised for it include “Something Posing As Meat”, “Stuff, Pork and Ham” and “Spare Parts Animal Meat.” Oddly enough, Spam wasn’t even the original name of the product – it was introduced because the previous name – Hormal Spiced Ham – was losing market share.

It wasn’t until Monty Python and Joel Furr got involved years later that the word assumed its modern meaning.

By the way: according to Hormel’s trademark guidelines, Spam should be spelled with all capital letters and treated as an adjective, as in the phrase “SPAM luncheon meat” – strange but true.

Referenced in:

Spam – Save Ferris
Spam Song – Monty Python
Spam – Weird Al Yankovic