Definitions
1.noun(grammar) The vocative case
2.noun(grammar) A word in the vocative case
3.nounSomething said to (or as though to) a particular person or thing; an entreaty, an invocation.
4.adjectiveOf or pertaining to calling; used in calling or vocation.
5.adjective(grammar) Used in address; appellative (said of that case or form of the noun, pronoun, or adjective, in which a person or thing is addressed). For example "Domine, O Lord"