When you reference parts of the pattern, you do so by naming them. The names you give the different parts are calles identifiers.

In this example: START n=node(1) MATCH n-→b RETURN b

The identifiers are n and b.

Identifiers can be lower or upper case, and may contain underscore. If other characters are needed, you can use the ` sign. The same rules apply to property names.

"start n=node(0) return n.NOT_EXISTING, n.`property with spaces in it`"