Right now we are learning about functions, relations, etc. and I am kind of confused.

Here is what I have to answer:

Determine whether each of the following is a function. Identify any relations that are not functions.

Domain
A set of avenues

Correspondence
An intersecting road

Range
A set of cross streets

I don't get how you figure out if these are functions or not. There are other similar ones, too, so please don't just give me the answer, but explain it, too.

Thanks so much! Any help is appreciated!