When Gomer Pyle used to say “Shazam!” as his exclamation, even back in the 1960s on the Andy Griffith Show, the older people would smile and youngsters would have no idea why he did that.
You see, in the very early 1950s there was a comic book with a superhero called Captain Marvel in it. When a new comic book company started the new Captain Marvel, and another started one called “Shazam.” They were entirely different.
Captain Marvel actually outsold Superman for a while. I believe those who owned Superman sued and got Captain Marvel stopped as plaguerizing on their earlier superhero.
So when I hear “Shazam!” I think of
When the boy who became Captain Marvel wanted to become the adult superhero, he would shout “Shazam! The next frame of the comic book would be a lightening bolt with BOOM! written under it. In the next frame Captain Marvel would replace the boy, whose name I forget.
All this is, of course, vital to information for you. To add for indispensable information, let me add that Shazam meant something like Solomon for Wisdom, Hercules for strength, Achilles for courage, and so forth.
I remember Captain Marvel especially because when I had to fill out forms for security clearance, I had to give EVERY organization I had EVER belonged to, and so I started with The Captain Marvel Club, which came before the Boy Scouts.