Bye-bye, indeed, Miss American Pie. If General Motors has its way, you won’t be driving your Chevy to the levee ever again.

On Tuesday, G.M. sent a memo to Chevrolet employees at its Detroit headquarters, promoting the importance of “consistency” for the brand, which was the nation’s best-selling line of cars and trucks for more than half a century after World War II.

And one way to present a consistent brand message, the memo suggested, is to stop saying “Chevy,” though the word is one of the world’s best-known, longest-lived product nicknames.

“We’d ask that whether you’re talking to a dealer, reviewing dealer advertising, or speaking with friends and family, that you communicate our brand as Chevrolet moving forward,” said the memo, which was signed by Alan Batey, vice president for Chevrolet sales and service, and Jim Campbell, the G.M. division’s vice president for marketing.