A widespread activity in religions of the proselytising kind comprises sending "missions" to convert and support new adherents. Some churches reflect the primacy of mission work in their structure and nomenclature. The term missionary stems from the proselytising sense of "mission". (see for instance: California mission).
The study of missions, particularly Christian missions, is missiology.
Analogously to the religious use, some businesses see and label their marketing practices as "missions". Other businesses may simply subscribe to mission statements as credos.