Definition of "Replacement" :

noun: the act of furnishing an equivalent person or thing in the place of another

noun: a person or thing that takes or can take the place of another

noun: an event in which one thing is substituted for another

"The replacement of lost blood by a transfusion of donor blood."

noun: a person who follows next in order

noun: someone who takes the place of another person

noun: filling again by supplying what has been used up