noun
plural -sions
[count] a task or job that someone is given to do
a specific military or naval task
a flight by an aircraft or spacecraft to perform a specific task
a task that you consider to be a very important duty
a group of people sent to a foreign country for a specific reason (such as to have discussions or to provide training or assistance)
a group of people who are sent to a foreign country to do religious work :a group of missionaries
a place or building where such work is done