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 person or thing that takes or can take the place of another
an athlete who plays only when a starter on the team is replaced
put in the place of another; switch seemingly equivalent items; "the con artist replaced the original with a fake Rembrandt"; "substitute regular milk with fat-free milk"
be a substitute; "The young teacher had to substitute for the sick colleague"; "The skim milk substitutes for cream--we are on a strict diet"
act as a substitute; "She stood in for the soprano who suffered from a cold"