what is koinonia?

It's a Greek Word.  Now, I'm not a Greek snob about the New Testament.  I don't flaunt the biblical language thing.  When I was a student in seminary, I took new Testament Greek.  The language opens up the scripture in ways that English sometimes doesn't.  It raises ideas and questions that English can't.  And it puts the Christian message in the language of its first audience. 
Koinonia is one of my favorite Greek words.  It means sharing, generosity, association, communion, fellowship, participation, a close relationship. And it describes what the first church looked like in practice.
The word is found in the Book of Acts, chapter 2 to describe the gathering of believers in Jerusalem after the day of Pentecost.  Describing the gathering the writer said, "They devoted themselves to the apostle's teaching and koinonia, to the breaking of bread and the prayers."  Acts 2:42.
This is what the first church looked like; this is what they did.  Four acts of devotion:  Apostles' teaching, koinonia, breaking of bread, prayers. So, they were students/disciples of the first followers of Jesus.  They likely heard the story of Jesus' death and resurrection.  But they may have also heard his teachings, parables, and stories of his miracles.  The disciples taught what their rabbi taught them.  According to the end of the Gospel of according to Matthew, this was Jesus final instructions to his disciples--to go and make disciples of all ethnic groups, baptizing and teaching them.      
Second, they practiced koinonia---they held a common life together, they shared. They participate in each other's lives, the struggles and joys of daily life.  They built strong relationships among those who gathered.  They developed friendships, kinships, bonds of love.  They were generous with one another.
Third, they broke the bread.  This was a reenactment of the last supper, of the supper at Emmaus, of the feeding of the multitudes.  It was the earliest form of the Lord's supper, Holy Communion, the Eucharist.  For them, Jesus was truly present in the act of breaking bread. He was in it with them and for them.  It was a meal that signified an end to hunger.  It was a meal that signified the forgiveness of sins. 
Fourth, they prayed.  How?  With the Psalms and with the prayer Jesus taught his disciples.  They would have adapted and adopted some Jewish prayers, too.      
So, what if the 21st century church adopted the practices and culture of the 1st century church?  What might that look like and sound like? 
First, it begins with the teachings of the apostles--the New Testament and the story of Jesus, the people of God, and the salvation of the world.  What did Jesus teach?  How did he teach it and to whom? Why did they form koinonia, a highly participatory community of people in relationships characterized by sharing?