a person who contributes to the fulfillment of a need or furtherance of an effort or purpose; "my invaluable assistant"; "they hired additional help to finish the work"
someone who assists a priest or minister in a liturgical service; a cleric ordained in the highest of the minor orders in the Roman Catholic Church but not in the Anglican Church or the Eastern Orthodox Churches
a knowledge domain that you are interested in or are communicating about; "it was a limited domain of discourse"; "here we enter the region of opinion"; "the realm of the occult"
territory over which rule or control is exercised; "his domain extended into Europe"; "he made it the law of the land"
the set of values of the independent variable for which a function is defined