What Makes a Church? (Or, why isn't my Home Group a church?)

I've been thinking a lot about what it means to "be a church," and more specifically, why something like an InterVarsity or Campus Crusade meeting doesn't really count as church; or why a 12-step meeting does not qualify. This comes after some extended reflection on the many ways that my current (and most excellent) home group functions as a church. And, while I have not come to any conclusions, here are some formal and informal ways that this amazing group of Christians functions like a church body:

• We gather each week in the name of Jesus Christ to hear and engage God's Word. (We have a regular teaching rotation)
• We worship with music and song each week. (We have a regular "worship team" rotation.)
• We regularly meet with one another for informal friendship/fellowship outside of the Home Group setting. (We have a sense of Community.)
• We go on retreats together as a community.
• We have a pastoral care/outreach ministry - providing materially (food and finances) for those in our community and elsewhere that are in need.
  
• We have an (admittedly informal) accountability structure.
• We have "small groups" within the larger group that pray for one another.
• We are multi-generational (well, at least partially. Folks in their 40's down to infants...If the infants ever will come!)
• We have our own online directory and home page.
• We are willing to provide child care.
  

According to a book on Vineyard ecclesiology that I have been reading, the following are "characteristics of an authentic church:"

• Where believers gather regularly in the Name of Jesus Christ for fellowship, worship, prayer, ministry and mission.
• Where the Word of God is faithfully preached
• Where oversight and disciple are properly constituted and administered
• Where the ordinances (sacraments) of Christ are properly administered
• Where recognition and respect is given by the broader Church

While I think that definition misses some important points, we fulfill 1 & 2, we at least partially fulfill 3 & 5. Because we do not think of ourselves as church, we do not yet fulfill 4. In any event, it is interesting to think about what constitutes a church, and which elements are important, and which come naturally (without much forethought).

Grace & Peace