"Christian Ministry......Is the public activity of a baptized follower of Jesus Christ flowing from the Spirit's charism and an individual personality on behalf of a Christian community to proclaim, serve, and realize the kingdom of God." - Thomas O'Meara
"Mininistry can be defined as "meeting needs with love." -Doug Fields
"Worship, edification, and outreach through evangelism and service - these constitute the mandate of the church... Thereby we bring glory to the triune God." -Stanley Grenz
"The service or work of sanctification performed by the preaching of the word and the celebration of the sacraments byt those in Holy Orders or in determined circumstances by laity. The New Testament speaks of a variety of ministries in the Church; Christ himself is the source of ministry in the Church. Bishops, priests, and deacons are ordained ministers in the chruch." -Catechism of the Catholic Church
So yeah, I have a paper due soon in which I need to define ministry, and explain that definition. The first quote is from one of our course textbooks, the second from Purpose Driven Youth Ministry, and the others are familiar. I noticed as I began this assignment that I don't currently have a working definition of ministry, which can cause trouble because I am a minister.
As I look at the above definitions none seem satisfactory (especially the Catechism's). O'Meara and Grenz seem closest to what I inately think is ministry. O'Meara captures an important point in 'flowing from the Spirit's charism' and Grenz does as well when naming ministry a 'mandate'. Yet, I'm not sure how I feel yet that O'Meara qualifies ministry as something done for the Church's sake. Doug I assume is deeper than his definition supposes, but probably dumbed it down for his audience (that includes me). The Catechism is too hierarchical, and treats the majority of the body as an after thought (that includes me again).
It seems the definition should include the following elements (whether named specifically or contained inherently): triune God, community, service, grace, reciprocity, open to all, just, commanded, and empowerment. It also seems appropriate that because 'ministry' as a subject is passionate and graceful the definition should be passionately and gracefully written, not dry, bland or subdued. And that is the real kicker, when defining ministry one is trying to define a word that has been defined so many times before, but in a way that is unique and appropriate for the context (that's kinda an apt metephor for life as well).
Additionally, the definition ought to be appropriate in all situations. Youth ministry, feeding the hungry, sunday school, public service, sunday worship, etc.