Why are organic elimination reactions known as beta eliminations? Why don't we call them alpha eliminations?
In an elimination reaction we typically have a leaving group (denoted by "X" in the figure below), The carbon that the leaving group is attached to is referred to as the "alpha" carbon. If a hydrogen is removed from the "beta" carbon, then we have formed an olefin and the reaction is called a beta elimination.
Sometimes an alpha hydrogen can be removed. In this case both the hydrogen and leaving group were attached to the same carbon and a carbene is formed.