The word spam cannot be found in Webster's Dictionary. I agree with Spam food?

[Cecile]

company and their concern. Canned Spam has been on sale in the grocery stores for at least 60 years and can be found on the list of Nutritive Value of Foods of the Taber's Medical Dictionary. When computer language was introduced, the word SPAM meant something unwanted, and could easily be associated with the food.

[Panama Joe]

This is a link from the Merriam-Webster site:

http://dictionary.reference.com/browse/Spam

The unwanted e-mail is the second definition. So it was easily found.