n.
1.an event in which one thing is substituted for another
2.the act of furnishing an equivalent person or thing in the place of another
3.someone who takes the place of another person
4.a person or thing that takes or can take the place of another
5.filling again by supplying what has been used up
6.a person who follows next in order
Idiom of the Day
build a fire under (someone)
to stimulate someone to do something
We keep trying to build a fire under our friend but he refuses to study or look for a job.