GTO, aka Gran Turismo Omologoto. The name makes perfect sense for the Ferrari that bears it. It is after all, a grand touring car, homologated for racing eligibility. How it came to refer to a variant of the Pontiac LeMans (and later Tempest) Sedan, is a matter of brilliant marketing. After all, what name implies of performance better than that of a world-famous race car? Though the name was originally borrowed from Ferrari, the letters GTO almost always now refer to the Pontiac.
This is a companion discussion topic for the original entry at https://www.hagerty.com/articles-videos/Articles/2006/09/04/The-Name-Game