ColdFusion EXtension - A custom extension to the ColdFusion web application language written in VC++ or Delphi. This definition has been altered slightly over time to now encompass ALL extensions to the ColdFusion language no matter what language it is written in (even native CFML).
Extensions can now be written in the following languages and methods:
VC++
Delphi
COM
Corba
Java
EJB
ColdFusion

Other languages can be hacked in by experienced ColdFusion programmers.