prepositions - "on" 7th Street and 8th Avenue

I live on 7th Street and 8th avenue.

What does it mean? How can you live on two streets?

Answer

It means, literally, that you live in a building on the corner, at the intersection of the two streets; but it is sometimes used a little more loosely to mean near the intersection.

How you express an address depends to some extent on context. If you are trying to communicate what part of the city you live in, a single street name may be uninformative, since a street may be very long and pass through many very different neighborhoods. “34th and Vine” will pin things down for anyone who knows the city and wants to know what neighborhood you live in, or how to get there and how long it will take.

Some similar expressions are

I live on 7th Street, at 8th Avenue.
I live at 7th Street and 8th Avenue.
I live at 7th and Market. (this obviously won't work if the streets in both directions are numbered)
I live on 7th Street, just off 8th Avenue.
I live on 7th Street, between 8th and 9th Avenue.
I live on 7th Street, two doors down from 8th Avenue.
I live in the 800 block of 7th Street.