Definitions
1.AdjectiveOf or pertaining to calling; used in calling or vocation.
2.AdjectiveUsed in address; appellative; said of the case or form of the noun, pronoun, or adjective by which a person or thing is addressed."In English, the vocative may be indicated by an addressee–address separation comma, or by the particle O, as in "What is the matter, sir?", "Mother, listen!", or "O Lord"."
3.NounThe vocative case
4.NounA word in the vocative case
5.NounA vocative expression
6.NounSomething said to (or as though to) a particular person or thing; an entreaty, an invocation.