Among Christian missionaries, the process or period of time during which they raise support in preparation for going to their mission field. This use of the word has been common in churches and mission organizations for over a century, but has recently been giving way to the more "bureaucratic" term "home ministry assignment". As commonly used, a missionary does deputation or is on deputation. However, the missionary is not called a "deputy" nor is the person said to be a part of a "deputation". Deputation begins when the missionary is officially commissioned to be a missionary, and it ends when the person goes to the mission field
The person or persons deputed or commissioned by another person, party, or public body to act in his or its behalf; delegation; as, the general sent a deputation to the enemy to propose a truce
A deputation is a small group of people who have been asked to speak to someone on behalf of a larger group of people, especially in order to make a complaint. A deputation of elders from the village arrived headed by its chief. = delegation. a small group of people who are sent to talk to someone in authority, as representatives of a larger group