What does "hero sandwich" mean?

A large sandwich on a long thick bun.

What is a synonym for "hero sandwich"?

Common synonyms include: bomber, cuban sandwich, grinder, hero, hoagie, hoagy.

noun

noun ·Rare ·Advanced level

Noun

1
A large sandwich on a long thick bun. US
2
a large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States wordnet

The New York term hero is first attested in 1937. Unlikely to be related to gyro, since those were not well known in the US at the time.