Missions
From MissionTechWiki
What is Christian Mission?
Well, it is simply God's ongoing plan to redeem all peoples of the earth. His plan started a long time ago, and we see evidence of it in the Bible right from the Garden of Eden in Gensis. Probably the clearest command in the new testatment, from Jesus to his disciples regarding mission is Matthew 28:16-20, otherwise known as the Great Commission.
In general Missions is the responsibility of the Christian Church to reach out to people who are not in a relationship with Jesus, to inform them about God, Jesus and his offer of salvation. It includes teaching and training them, otherwise known as discipleship.
Cross-Cultural Mission
The Church very easily gets stuck and if it reaches out to others, it often only reachs those who are the same, ie, those who speak the same language and culture. In some ways that is understandable becuase those folk are easier to talk to. But God is interested in bring all peoples back into relationship with Him. In Acts 1:8 Jesus tells his disciples that he will empower them to be witnesses in their own culture (Jerusalem and Judea), in a related culture (Samaria) and to all people.
So when I talk about mission, I mean cross-cultral mission.
More Info
Here are some sites thatgive more information. However so far I haven't found anything that actually explains what mission is...