This is the 7210th most frequent Spanish word.
gmc
It seems "gmc" is not a Spanish word. It may refer to something else, such as an abbreviation.
In this sentence, 'GMC' is used as a proper noun referring to the General Motors Company, an American automobile manufacturer.
Mi amigo trabaja en GMC como ingeniero automotriz.
My friend works at GMC as an automotive engineer.
Here, 'GMC' specifies the brand of the truck seen, emphasizing it as a brand name in context of automotive vehicles.
Vi una camioneta GMC pasando por la calle esta mañana.
I saw a GMC truck driving down the street this morning.
In this instance, 'GMC' again refers to the automobile company, focusing on its production of electric vehicles, showcasing its use in discussions of modern automotive technology.