Fashion week/"7th on sixth"...huh?

It’s Fashion Week here in NYC, and the official name of the show each year is “7th on Sixth.” What in the name of Gucci does this phrase mean?

The design houses on 7th Avenue have their fashion shows on 6th Avenue. There’s an actual corporation called “7th on Sixth” that coordinates fashion week. They kept this name even during the year (two years ago?) the shows were held in a different location.

Ah. The “Fashion Ave.” folks in Bryant Park. Makes sense.
Thank you.