Replacement definition

(1) The act of furnishing an equivalent person or thing in the place of another

"Replacing the star will not be easy"

(2) A person or thing that takes or can take the place of another

(3) An event in which one thing is substituted for another

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

(4) A person who follows next in order

"He was President Lincoln's successor"

(5) Someone who takes the place of another person

(6) Filling again by supplying what has been used up