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
(medicine) the act of caring for someone (as by medication or remedial training etc.); "the quarterback is undergoing treatment for a knee injury"; "he tried every treatment the doctors suggested"; "heat therapy gave the best relief"