1 a a particular task or goal assigned to a person or group. b a journey undertaken as part of this. c a person's vocation (mission in life).
2 a military or scientific operation or expedition for a particular purpose.
3 a body of persons sent, esp. to a foreign country, to conduct negotiations etc.
4 a a body sent to propagate a religious faith. b a field of missionary activity. c a missionary post or organization. d a place of worship attached to a mission.
5 a particular course or period of preaching, services, etc., undertaken by a parish or community.
Etymology: F mission or L missio f. mittere miss- send
Useful english dictionary. 2012.