■ noun
1》 an important assignment, typically involving travel abroad.
↘[treated as sing. or plural ] a group of people sent on a ~.
↘an organization or institution involved in a long-term assignment abroad.
↘a military or scientific expedition.
2》 the vocation of a religious organization to spread its faith.
↘a building or group of buildings used by a Christian ~.
3》 a strongly felt aim or calling.
Origin
C16 (denoting the sending of the Holy Spirit into the world): from L. missio(n-) , from mittere 'send'.