The word relay in a much more general concept, means to replace someone with another. Its most common use is to refer to the action of impersonating an individual, either from their job or activity that they habitually perform. For example: "Pedro's replacement has not yet arrived and his watch is about to end."
Once the person is replaced, he will no longer be able to continue performing the activity he was doing, but now, whoever relieves him will be in charge of executing the same activity.
In the medical, military, public security organizations, etc. The term of relief is usually handled, since the functions of the people who work in these fields is by guard, therefore, the image of the relays is always present.
Now, in sports the word relay is also used, especially in regards to athletics. In this sports specialty, the relay is a practice that consists of forming teams of four and where one of the runners travels a specific distance, and then passes a kind of metal tube called a "witness" to one of his companions, who will relieve him and the tour will continue, then he will pass it on to the other and so on progressively until the end of the race.
In relay races, a team can be disqualified if, for example: the metal tube falls to the ground. If at the time of making the exchange, it is not done correctly. If the path of the other athlete is obstructed, among others.
