from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Slang A job, usually in the retail or service sector, that is low paying, often temporary, and offers minimal or no benefits or opportunity for promotion.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A job paying low wages, requiring few skills and having little opportunity for promotion.
Mc(Donald's), trademark of a fast-food restaurant chain (from its mass-produced nature) + job1.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Mc, from the name of the restaurant chain McDonald’s, + job, jobs in McDonald's being considered to be this sort of job. (Wiktionary)