Vecchio

Very colloquial, friendly contest. Typical in North Italy. Often following "Bella!".

Used to address someone you perceive nor inferior or superior to you.
It is similar to the american use of "man" (hey, man!), doesn't imply great closeness between two persons, but there may be. Often completed with a fist bump.

Ciao vecchio, come va?
Bella, vecchio!
Scusa vecchio, hai una cicca (sigaretta)?